I started with an 0 Coast, and following a suggestion here or on Reddit I added a Warps as my first “real module”, quickly followed by Marbles and Links/Kinks.
Warps has so much to offer and I still have it in my rack many years later, I absolutely love the two ring mod algorithms, the crossfolder superb for destroying a signal with some audiorate modulation, the overdrive on the inputs…it’s all so good. You also get a VCO with VCA on channel 1 when you’re not using the channel 1 input. It really is a delight.
Marbles continues to surprise and delight and I feel links/kinks are no brainers as they will always be useful see here (Ideas for Links and/or Kinks?)
TL;DR, have you thought about Warps?