You might want to check out the roli seaboard, I have one and it's great for playing synths. A bit pricey but I enjoy it a lot. I got it because I was tired of

You might want to check out the roli seaboard, I have one and it's great for playing synths. A bit pricey but I enjoy it a lot. I got it because I was tired of making music through a UI and wanted to 'feel' it more like I do on the guitar. I would also say any MIDI compatible keyboard is a good fit too, try to get something that has a pitch wheel though. The wheel will let you "bend" your sound and add some expressivity that just hitting the keys won't. I still think a midi keyboard is the best first interface for people that want to step into synth music.