I am considering adding a small synth that supports CV in and Gate to my setup (as I have a couple of Eurorack sequencer I would like to take advantage of). What is currently available on the market that is not too pricey but still fun? Something alongside the MFB Nanozwerg would be perfect. Thank you 
I would say the make noise 0-coast as that is super fun imo but that might be a bit too pricey? The moog werkstatt with CV expander is pretty cheap and should be fun to patch with a sequencer or two
Yeah I would say look at the 0coast from Make Noise, Pico System 3 from Erica Synths, and Pittsburgh Modular makes 3 really cool looking ones in the Lifeforms Voltage Lab, Lifeforms SV-1B and Microvolt 3900.
Also the nearly every Dreadbox monosynth.
Most semi-modulars use V/Octave, but I believe the modern Korg MS20 and Behringer K2 still use Hz/V, but there are converters.
Mini? I liked the Plankton Ants, Dark Energy 1, Boomstars, and Pittsburgh Modular standalones. But those Behringers and the MiniBrute 2S are dirt cheap. The Elta, SonicSmith, Bastl, JMT, and Rare Waves stuff looks interesting. And you can still find the older small Analogue Solutions Station X.
Just to get an idea of whatβs out there (filtered by price - low to high):
Standalone Semi-modulars.
Or get a bigger case and a full voice module.
On Reverb, search for Semi modular.
thanks everyone for the nice recommendations 