Since you have ths FX Aid, you may also like Happy Nerding's 3xMIA and 3xVCA. If a matrix mixer (which is actually a great tool in Eurorack because you can use it to mix, route, and reroute CV for lots of detailed transitions) is too big to fit in, this may also give you some good modulation mixing/changing options. For the 3xVCA, one thing I like other than the attenuator for the input CV is the switches you can use to send the output of a channel to the next channel, allowing you to easily multiply or mix signals together at the literal flick of a switch. Simple utilities, but super playable and really useful.