I've seen people ask for recommendations on anime and gacha games; but as far as I care to look, which is not very far, mind you, there is not a thread asking for recommendations on Bullet Hells...
You know, the very thing Touhou is known for?
So I decided to remedy this perceived problem by asking the Moriya Shrine in general: What (hybrid) Bullet Hells do you recommend that you have played and, if applicable, what (hybrid) Bullet Hell you playing now?
I myself am currently playing "Last Command", which combines snake with Bullet Hell elements and a story that hits way too close to home for me in the three hours I've already played. I haven't been that emotional for as long as I can remember, but i digress. The game follows a program called Python as it explores the world of programs and computers in a post-human era. It must fight programs in a bullet-hell like fashion in order to not get deleted. (Or at least that was the reason the four bosses I have fought in 3 hours of playtime had.)
For recommendations, I'd give "Bullet Heaven 2" the (dis)honour of my recommendation. Half because it is the only non-Touhou Bullet Hell I have played and half because it is at least a decent Bullet Hell in my experience. It follows the misadventures of Matt, Natalie, a fascist, Anna and a cat without legs capable of shooting stars as they go across their globe on the whims of fate.
Though I'd be happy with any recommendations for more 'modern' bullet hells, as I believe there exists three in semi-popular conscience if you don't count Touhou.