Used to be mainly niche but these days probably 50/50 maybe leaning more to popular games with the current decline in jrpg's and there move to mobiles.

I consider myself a good mix of both

As it should be.

both depending of my mood

This. it doesn't make any sense to me to categorize "niche", "popular" and "mainstream" as genres, and I couldn't care less about how many others enjoy a game as long as I do.

Checking my Steam account the last games I bought are

Niche: Technobabylon, Astebreed, Vessel, Cosmochoria, Tengami, Secrets of Rætikon, Armello, Morningstar, Train Fever, Hand of Fate.

Popular: Life is Strange (before you question the popularity of this game: It already has more than 280.000 owners on Steam alone), Pillars of Eternity, Cities: Skylines, Star Wars KOTOR I and II, Age of Wonders III, Napoleon: Total War.

Guess I lean more to the niche side, but I have nothing against popular games, if they're up my alley.

I'd probably say mostly niche. There's a reason why I have to buy a lot of my games day one. Wait too long and then they are gone.... and on amazon for a ton of money...

I've usually gotten more popular games but I've been delving more into niche games recently.

probably niche, especially since last gen
discovered so many cool series last gen, and I'm glad to see them growing and carrying on into this gen.

Niche 4ever