2018 is drawing to a close. We have one more first party release for Nintendo Switch left before we move into 2019. 2018 was an interesting year, in that it served as a weird transitional year for both Nintendo and the Switch. Most of its internal staff was just coming off two of their biggest productions yet (BotW and Odyssey), and no doubt they're hard at work on a new sizable batch of Switch games. The release slate of 3DS games has slowed to a trickle, the online service for Switch formally debuted (abiet to largely mediocre reception), and Nintendo itself went through a few changes with Tatsumi Kimishima stepping down back in June, handing the reigns over to Shuntaro Furukawa, who helped mastermind the console's record-breaking launch. So for this year on Switch, Nintendo mainly relied on Wii U greatest hits, DLC expansions, and Third party games to do most of the heavy lifting with some new games in the form of Kirby, Labo, Mario Tennis, Super Mario Party, as well as Pokemon and Smash Bros. spruced in-between. I'd say 2018 had more good games, but 2017 had bigger titles (In B4 "2018 was awful because I didn't get x, y, and z. Switch has a drought, wah!").

So that brings us to 2019, which is where things really start to get interesting. 2019 is when the Switch will truly start feeling like the 3DS successor everyone wanted and Nintendo likes to avoid admitting, since many of the former's well known series will be getting sequels on Switch. Fire Emblem, Luigi's Mansion, Animal Crossing, Pokemon, etc. Nintendo will also reduce its reliance on ports next year as most new Switch games that began development around the time the system launched, will be ready by that point, and with hardly any new 3DS titles next year, we could see even more Nintendo published games than this year, including internal ones from EPD. So here's how I think the lineup will go down, rather here's what I hope to see in 2019.

January - New Super Mario Bros. U DX, Fit Boxing (Nintendo published outside Japan)

February - Dragon Quest Builders II (Nintendo Published outside Japan), Puzzle League Forever

March - Yoshi's Crafted World, Nintendo Labo: Toy-Con 04 - Outdoors Kit

April - New digital IP (something along the lines of Snipperclips)

May - Fire Emblem: Three Houses, Daemon X Machina (Nintendo published outside Japan)

June - WarioWare: Freestyle, Luigi's Mansion 3

July - New IP, Nintendo Labo: Toy-Con 05 - City Kit

August - ARMS II, New IP

September - Pokemon Rose and Violet, Wii U port (Pikmin 3?)

October - Fire Emblem fighting game by Arc System Works, New Casual IP

November - Metroid Prime 4: Desolation, eShop only game

December - Animal Crossing: Road Trip

That's my prediction/wish-list for 2019. I think next year is when the Switch will really start hitting its stride. By this point, all of their developers are done with 3DS projects, a new batch of Switch titles from Nintendo will be ready, and third parties will help as well as more of their original titles will be ready as well. If you thought 2017 was great for the Switch, it's just getting started.

Arms 2 and Metroid Prime 4 eShop only .... are you trying to be wrong?

I meant Metroid Prime 4 PLUS an eShop only game releasing the same month. Not Metroid Prime 4 being eShop only. Also, many of these aren't for sure predictions, just stuff I would like to see in 2019.

Earlier you said "New digital IP", so the wording was confusing. I would have assumed you'd just say digital only game. 

Anyways, I don't really see why Arms 2 would release next year speculation-wise, but if that's what you want that's what you want. 

Pokemon Rose and Violet? i would have gone with something more bold like Crimson and Cobalt, but hey thats just me

Not sure about that name the names Rose and Violet. At this point, I've grown pretty fond of Plus and Minus.
Regardless, I'm 99.9% certain Pokemon Gen 8 is the holiday title, just like this year.
I'm also 99.9% certain Metroid Prime 4 will NOT be a 2019 title. I'm thinking that will be a 2nd half 2020 game.
I believe Luigi's Mansion 3 is going to be in October. Makes sense considering the haunted mansion theme and Halloween.
Also, I don't think we'd get an Arms II this soon. They may do with that what they have done with Mario Kart and Smash Bros., one per system. (Though Mario Kart may break that trend.)
Finally, I think Animal Crossing will come out before Pokemon. Probably in July or September.

would love to see metroid prime trilogy and pikmin trilogies on the Switch, they'll be day one purchases for me even though I've played the series to death I would just love to have them on the Switch.

January: New Super Mario Bros DX
February: Metroid Prime Trilogy HD
March: Yoshi's Crafted World
April: Labo Kit, Vanquish Switch Edition
May: Fire Emblem: Three Houses
June: Luigi's Mansion 3
July: Town (GameFreak, eShop only), Star Fox: Grand Prix
August: Daemon X Machina
September: Bayonetta 3
October: Animal Crossing
November: Pokemon Generation 8
December: Metroid Prime 4

The biggest question marks are Bayonetta 3 and Prime 4 - they could easily be 2020, but I'm hoping for next year for both of them. Similarly, I'm hoping Prime Trilogy gets a HD remaster. My big hope is a Prime 4 gameplay reveal and Prime Trilogy HD announcement at the Game Awards.

Rumours flying around suggest Platinum have as many as three Switch games in the works - my assumption is Bayonetta 3 plus a port plus another new title. My guess is the port is either Wonderful 101 (quite likely) or Vanquish (less likely, but I'd prefer to see Vanquish next year). As for the other games, Yoshi in March makes sense, Fire Emblem has launched in May in the West for each 3DS iteration, Town strikes me as a self-published digital game from GameFreak (doesn't appear on Nintendo's own release lists, so maybe shouldn't be on my list), I'm guessing Daemon X Machina isn't launching in the first half of the year but will launch in a traditionally quiet period.

I also think we'll see Luigi release before Animal Crossing - we actually saw gameplay footage of Luigi, whereas the Animal Crossing reveal was not in-game footage. Nintendo will have released Smash Ultimate 9 months after the initial reveal, my guess is something similar happens with Luigi. It also gives them a stronger release slate than 2018, where-in Nintendo went most of the year without launching a bigger game. Mario DX plus Luigi should mean two 5 million plus sellers launch in the first half of 2019. Fire Emblem should land in the 2 to 3 million range. Animal Crossing I think will get the October slot - like Super Mario Party, it's a family friendly franchise. Pokemon gen 8 occupies Pokemon's usual November slot, and Nintendo's December release will hopefully be Prime 4. Bayonetta 3 is down as September, which has had smaller titles launch in the past (Torna - the Golden Country this year, for example).

I've put Star Fox: Grand Prix down for July as a wild-card option. I hope/expect we'll see something from Retro Studios next year, but I'm really not sure when to expect it. Primarily sticking it in July was a way of balancing out the release list. Nintendo have launched some high-profile games in that June/July window - Arms and Splatoon 2 in 2017; less high-profile this year with Sushi Striker and Octopath Traveler. I think we'll see at least one more Labo Kit, but it really doesn't seem to have caught on the way Nintendo wanted.

Basically 2019 should be a strong year for Nintendo. With Animal Crossing, Pokemon, Luigi's Mansion 3, Daemon x Machina, Yoshi, Mario Bros U DX and Fire Emblem: Three Houses 'confirmed' for the year so far, and with Metroid Prime 4, Bayonetta 3 and Retro Studio's game being other potential 2019 games, I think we have an exciting year coming for original, Nintendo-published games.

I think 2019 could surpass both 2018 and 2017 combined in terms of original games and quantity of games Nintendo publishes. Nintendo published more Switch games this year than 2017, but they released bigger titles in 2017 than this year. Aside from Smash, nothing this year really reached the hype and anticipation of BotW or Mario Odyssey. 2019 is when the Switch is looking to be when the merger of home console and handheld resources really comes into fruition. No offense, But I personally think your list is a little too conservative. Then again, mine may not be that realistic either. 

My guesses at the moment are pretty similar to others:

January: New Super Mario Bros DX
February:
March: Yoshi
April: Fire Emblem
May: Star Fox: Grand Prix
June: Luigi's Mansion 3
July: Town (GameFreak, eShop only)
August: Bayonetta 3, Daemon X Machina
September: Pokemon Generation 8 (XY released in October, and every other mainline game prior to it released in September in Japan; I can see them going back to it to space it out among the other huge hitters)
October: Animal Crossing
November: Metroid Prime 4
December: Zelda BOTW sequel (to be teased in Jan direct; going off of GameInformer's speculation that the next Zelda is closer than we think and assuming a Majora's Mask-esque sequel on the same engine)