There are a few, some of which I did go back and finish, and others that I didn't.
-Resonance of Fate. Stopped playing around 15 hours in when I hit a boss that just kept beating me no matter what. Then literally years later decided to go back and finish the game, which I actually did.
-Resident Evil 4. Played maybe halfway through before stopping. No particular reason, I've just never gone back to finish it.
-Devil May Cry. Same thing, although I was probably even further in by the time I decided to take a break, and then just never went back.
-Dark Souls. Originally played for maybe 10 hours, but just couldn't get into the game at all. It just didn't click with me. Then maybe 2 years later I decided to give it another chance, and now it's among my all time favourite games.

Oh, that reminded me of that one. The game was fine but I got tired of the dungeons, numerous areas the same, do backflip, shoot enemy. I just kind stopped. I was thinking about getting the remaster to see if I have a better time.

Thinking back, I did the same for Rogue Galaxy, I hit a moment in the game where the main character gained super saiyan powers and the story kind lost me and I stopped playing, was fun until then.

I did the same with Valkyrie Profile 2 in the 2000s, infact bought it again recently (last few years) and completed it this time around as I got past where I got stuck as I actually had a character/weapon that was op, so was able to get past the area I was stuck at, being older allowed me to understand it better too.

It's a bit concerning a lot of games mentioned are JRPGs, no?

I have never stopped playing a single player game for more than three days and have went back to it 

chrono Trigger I quit and got back to, about 10 years later, haha. Eternal Darkness and Pikmin 2, too, although those two only had to wait about 5 years.

So maybe there is hope for games like Tales of Symphonia, Skiesof Arcadia and Ogre Battle 64. Basically I could not find the time to finish RPGs in my dating years.

Wouldn't call it a travesty, but lots of things just didn't feel "right". Especially the fact that world wasn't physically connected like Lordran and Lothric. Real Immersion breaker.

The thing about Matterfall though, is it's pretty tough, and requires mastery of fairly complex technique. It's one of the more difficult side scrollers I've ever played. I was in a nice ryhthm, and would have to get back into it. As you say though, it's a short one, which is a plus. Dead Nation, like Matterfall, is a Housemarque game, and maybe my favorite of all of them ( I own 10 of their games across PS3, PS4 and Vita ). It's a top down, twin stick shooter, where you play not only to pass missions, but also for score and money. You collect money to buy new weapons and gear, which you also purchase upgrades for. It's the game so nice I own it thrice, with plats in the PS3 and Vita versions. It's currently $15 on the NA PSN. It'll almost certainly be on sale at some point too. It also has a co-op mode, and while decent fun, I prefer solo.

I will. And it wasn't just those two. Tons of games from Infinite Undoscovery, GTAV and Red Dead 2 to Vanquish and NSMBU (Wii U version). Something comes up and before I know it, a year has passed. In fact, I bought Xenoblade for Wii, didn't beat it and bought it again for the 3DS...only to not beat it! I suck sometimes.

Legend of Zelda:  A Link to the Past (started 1991, finished 2018)

Suikoden (started 1997, finished 2009)

Luigi's Mansion (started 2002, finished 2017)

Fire Emblem:  Awakening (started 2012, finished 2019)

All games that I put significant time into, but for one reason or another had multi-year gaps in playtime before I returned and completed.  It gives me hope of finishing other games that are in my deep, deep back-log.

God of War 1, got so tired of the QTE-crap that i rage-quit about 75% through and never returned
Final Fantasy 6 and Octopath Traveler, played them for about 30 hours, then stopped and i am not sure if i will ever return

I came back to Windwaker after setting it down a couple years earlier and finished it.