What platform? I can think of multiple must buys, but it really depends on the system.

You can't buy them anymore. They're all got delisted from every store by the publisher.

I'm currently addicted to Chained Echoes, a 2D SNES style rpg adventure.

Pathologic 2! It's so good! And the next one is coming out next year so it's a great time to become obsessed with Pathologic!

Rain World hands down, such an interesting and challenging game.

omori

RoboCop: Rogue City

Celeste absolutely! It's difficult but it's really really fun and has a great story. If you ever get super invested, the community is great and the skill ceiling is so high that you can always get better when playing new maps.

First off I have to show my lack of taste by mentioning I will play any mainline final fantasy game.

But games I recommend and will likely buy the next ones are Persona 3R/4G/5R and The Witcher 3 with DLC / Cyberpunk 2077.

All great games of high quality, though some do not like the W3 combat mechanics.