Obviously it's a case by case thing, but in general do you find that you like games/consoles that sell well, or do you mostly like less commercially successful games/consoles and dislike the popular stuff?

Well my top three favorite consoles are NS1, GCN, and N64. I’ve never been a fan of handhelds… so can’t say I lean one way or the other. Same can be said about my favorite franchises: Mario, Zelda, and Pikmin. Two that are commercial juggernauts, and another that is a tad bit more niche.

No, they don't really align with the market very well. Of course some, probably even many, of my favourites are very successful commercially, but I'm generally not particularly interested in the games that the market is crazy about: the likes of GTA, Call of Duty, Fortnite etc. One part of that is that I'm just not very much into online multiplayer because of people and probably design as well, the other is that many such games are designed to accommodate for the lowest common denominator - which can definitely be fun, but it can only go so far for me.

As for consoles, it's always been PlayStation for me, but the reasons behind that are largely historical: When you're a kid, you get what your parents get you, and for me, that was PlayStation. PS2 was a natural follow-up, especially with some sequels to familiar games, and then PS3 was an even more natural follow-up to PS2. The first Xbox was never an option, and it was also really ugly with a terrible controller and no interesting games, and there was little reason to go for Xbox 360 instead of PS3 for me. Then comes Xbox One with its screwups, and PS4 it is, no competition - and it's the same story with Series S|X and PS5, except PS5 is terrible as well, but at least it has a future.

Notice how I haven't mentioned Nintendo. That's simply because I got a PlayStation and was happy with it. Nintendo always seemed cool but not interesting enough to really get excited about. I'm sure the games are fun, but they haven't really appealed to me enough to really get into Nintendo. I have a Wii, but I've used is very little. I'm more interested in a Switch (2), but I really want to finish to Wii backlog first... but it hasn't gone too smoothly.

So yeah, for consoles, it's mostly history. Somehow I also got into PC gaming, probably also because of kind of historical reasons, and that's what I've been enjoying the most, aside from some console games.

Depends, does PC count? I'm a PC-Steam gamer, and I suppose PC is the market leader when it comes to gaming.

Other than that, my favorite consoles are SNES, PS2, PS1, and Wii. All of them were very well received by the market, so, yeah, I think I usually agree with them.

I can't agree with GTA, though. I have zero interest in GTA VI, and never understood why this franchise keeps breaking records.

The things that sell the most are generally not my most liked games or consoles. But pretty much all games that I like are very popular, just not at the top.
Games with abysmal sales are however never games I like. But that might have as much to do with me never get to try them in the first place.

Of the consoles I have owned my two least favorite ones the WiiU and PS2, a failure and the most successful.

When it comes to whole gaming genres the story might be another one. Most of the best selling or most played genres are uninteresting to me. Arena battlers, FPS, Open World, what ever Pokopia and Animal Crossing is, and I see no point in playing most sports or racing games (compared to playing them irl).
But my most played and liked genre is still the most popular one in general, Action-Adventure.

So my taste is not an outlier in any sense.

Everybody thinks they're #notlikeothergamers. I'll play a few best sellers in a given year (such as GTA6), but I usually don't feel the need to jump on bandwagons, be it playing games because they went viral on social media or dogpiling on games that gamers have decided they hate/are shit without even playing them.

LOL not everybody (exception that proves the rule) .  I am the only one that selected yes in the poll so far.

Been a Nintendo gamer since the NES and had every Sony home console since they hit the scene.  I only ever had the Master System from Sega and I got that one way late.  Although I've bought X-boxes they have always been for the kids and not for me, same with handhelds.  I went from original GameBoy to New 3DS XL and although it was the cool Zelda one, I haven't played it more than a few hours so it was a wasted purchase.

I haven't gamed on PC since Warcraft 3 was new but, with the way Sony is going, I may forgo the PS6 and get a gaming PC instead.

Not nowadays. I was big into Mario when I was a kid but not anymore and I still haven't played even one second of any Pokemon game. Outside of open world Zelda, the games I play are niche.

I've never been a fan of Nintendo so....

What about Sony?  They have spent more time as the market leader than Nintendo has in the last handful of generations.