I'd like to underline the recommendations for Octopath, Xenoblade and Captain Toad but one of the great things about Switch is that you don't have to pay full price to get an amazing gaming experience. Of the shorter games that came over from PC do try Inside, Abzu and Gris which are wonderful little contained experiences that don't cost the earth and merit replaying. The best approach is to come up with a longlist of things you want to play and just wait for them to be on offer, since discounts have been rather common on Switch.

Also, shoutout to Diablo 3 which eats up the hours on Switch and is a very polished port.

FPS? while it's a TPS, try Splatoon 2

As for RPG, Xenoblade Chronicles 2, obviously. Also, give Golf Story a shot, really worth it. The Grandia I and II remasters and the Final Fantasy remasters might be interesting if you missed them before. Edit: How could I only forget Octopath Traveler? Get it! Right Now!

I don't know what other consoles you own, so not sure if I should suggest some multiplat titles which didn't make it to PC.

If RTS includes Tower Defense games, there are a couple of them on the Switch, most notably Aegis Defenders and PixelJunk Monsters 2. Also, there's Constructor Plus and Swords and Soldiers I and II (only played the first one on my Wii U, not bad at all, but totally moronic plot) as interesting RTS titles. Valkyria Chronicles 1 and 4 may be very interesting for you too, as they blend RTS, Turn-based Tactics and RPG into one

Oh, and on a general note, look at the link in my signature. It hasn't been updated for a while now (really need to find some time for that!), but might give you some pointers.

You have already Smash Bros and Zelda, other few must have Switch games are Splatoon 2, Mario Odyssey, Mario Kart.
If you love 2D platformers, buy DKTF and NSMBU DX.

For you, like many others have said, Xenoblade and Octopath traveller. To play with your son i would recommend Mario party, kart and odyssey. Just about anything Mario really.

These games should keep you entertained and fill a lot of genre holes.
Zelda BOTW
Mario Odyssey
Mario Kart 8
Octopath Traveller
Smash Brother Ultimate
Splatoon 2

Apart from the obvious recommendations (Mario Odyssey, Mario Kart, Smash Bros, Splatoon), the two South Park games available are insanely fun/funny and are always on sale. Also:

-Doom and Wolfenstein were ridiculously good, considering the limitations of the hardware
-Do you like beat em ups? There's Raging Justice, Double Dragon 1 and 2, River City Ransom (Nintendo Switch Online), Capcom's Beat Em Up Bundle
-Civilization VI is insanely fun, once you wrap your head around it.
-Dark Souls is frustrating as hell, but it's a great game and it's so cool being able to take the game with you, anywhere.
-Golf Story.
-If you liked the old SCUMM games of old (Maniac Mansion, Full Throttle, Monkey Island), Thimbleweed Park is a must!
-Hollow Knight! A game that every Switch owner should try!

This game was definitely robbed at the Game Awards...

Based on your criteria: Strategy, RPG (especially western), FPS and kid friendly, this is what I would recommend (from highest to lowest).

1.  Mario + Rabbids Kingdom Battle - It is a shooting strategy game with RPG elements, and it is silly hilarious which makes it entertaining to kids.  You will have fun playing the game and your kid will have fun just watching.

2.  Valkyria Chronicles 1 and 4 - These are shooting strategy games with RPG elements set in a fantasy WWII setting.  You will enjoy the hell out of these games.  While the visuals would appeal to a kid it does have a lot of adult themes to it.  There is no nudity or graphic violence, but the plot does talk about the horrors of war.  (These games are also on the PS4, but I would recommend them on either platform.)

3.  Hyrule Warriors - I played this on the Wii U and it is extremely fun.  It's a lot like Dynasty Warriors, but I enjoyed it a lot more than any Dynasty Warriors game.  My daughter was 6 at the time, and we could play together.  Really great local co-op.  She could mindlessly kill stuff and I would run around and complete the objectives if they were a bit on the tricky side.

4.  Dragon Quest Builders - This is a cross between Minecraft and Dragon Quest.  It's a sandbox with some objectives and quests thrown in.  I personally prefer it to Minecraft, because I prefer to have some objectives instead of just a pure sandbox.  (This game is also on the PS4, but I would recommend it on either platform.)

5.  Octopath Traveler - This is definitely a JRPG.  However, one reason I really liked it is that it has much more of an open world than a normal JRPG.  (I kind of think of it as a WRPG world design with JRPG mechanics.)  Also, the battle system is really fun and the music is fantastic.

6.  Mario Kart 8, Super Mario Party, Super Smash Bros. Ultimate, Puyo Puyo Tetris - None of these fit your genre specifications, but all of them have local co-op that is very kid friendly (depending on how old your kid is.  They probably need to be at least 5 to be able to play these games at a basic level.)



Here are some other games which I haven't tried yet, but would recommend anyway.  I will play them as soon as I wrap up Valkyria Chronicles 4.

Civilization 6 - I haven't played this entry yet, but this is probably the best strategy game series ever made.

War Groove - Plays like Advance Wars but in a medieval setting.

Dragon Quest XI S - It's a JRPG, but still looks great.  (Also it's on PS4.)

Well, as I do for such question I point to the collective wisdom of VGC-users which for Switch recommends 61 titles: http://gamrconnect.vgchartz.com/post.php?id=8956012

For RPG I would say it is always worth to check out Octopath traveler, it has a demo in the eshop to gauge if it is your cup of tea. If you more into strategic classic western RPG, Switch also has Wasteland 2 and apparently gets Pillars of Eternity 2 and Pathfinder Kingmaker (all three are Baldur's Gate/classic Fallout style of games, where you control a party of characters in isometric view with pretty complex and deep roleplaying statistics system). For JRPGs Xenoblade Chronicles 2 and Ys VIII are clear recommendations for action style JRPGs with big story and exploration. And you also need to have Pokemon on the radar, which comes later this year. For an Etrian Odyssey style game you might wanna check out Labyrinth of Refrain: Coven of Dusk (what a mouthful). NIS generally has gone full into Switch support mode, they have released nearly everything in their catalog, so you might check out what they offer. Noteworthy surely also is Disgaea 5. Besides that I hear good things about Tales of Vesperia. And you have a lot of smaller RPGs, like Darkest Dungeon, Banner Saga or Battle Chasers Nightwar.

A listing of First Person Shooters on Switch can't go without Doom. With that out of the way, Switch isn't the strongest platform for FPS. You can get all the free to play stuff, and much of it is pretty good. This includes Fortnite, Paladins and Warframe. I would recommend to check them out, as you have nothing to pay to play at first and you can decide if you wanna dive deeper. It has got some support from smaller FPS though, that target old-school-type FPS like Immortal Redneck, Apocryph and Ion Maiden.

Real-time strategy on Switch (or console in general) is not something I am very aware of. I know Switch has Townsmen and Mushroom Wars. Seemingly some include MOBAs into this category, so here you are set with Arena of Valor and Smite.

Should a toddler play video games?

Well, I am not too sure about what qualifies as good games for small kids. I assume something you can play together and is easily accessible. I would say Super Mario Odyssey might qualify. You might also take a look at Katamari Damacy (has a demo), this might or might not be viable for a child. And Mario Kart probably works for all ages.

1.+2. I excluded them because they are turn-based not real-time, but they are definitely great strategy games.

3. Hyrule Warriors works for small kids? Never would've thought that. But yeah, good game.

4. I definitely missed that one. I love DQ Builders. Not in the genre list, but might work for kids. Although the quests involve reading the text from the characters, so maybe not for a pre-school kid.

5. Yeah, Octopath is a great RPG. And people who are unsure can try the demo to get an impression.