If you want buttons, for mouse the Logitech G502 Proteus Spectrum has 11 buttons. If you need more you could consider one of those Naga-style MMO mice.
Keyboard is highly personal. I like the WASD Code keyboards with MX Browns. Do some research at mechanical keyboard communities like /r/mechanicalkeyboards on Reddit. Lots of good info.
Headset I recommend the HyperX Cloud but you could spend more and get a good set of headphones and a higher end mic like a Blue Yeti (or just a ModMic or clip-on mic).