Seconding all of farkas's suggestions... filter, VCA/mixer, EGs.
Also:
A mixer/attenuverter would be great. Either something like Shades, or something a little more complex like 4ms's SISM.
Some sort of random source / noise / S&H / etc.? Wogglebug, Nano Rand, etc.
A delay. Again, not entirely necessary, maybe, with the microcosm and Beads... and the tape delay in the Disting is very nice, too. But I dunno... I find that I can't have too many delays. One of the Noise Engineering Versio modules might be great here, as you can use it for several different things... delay, granular, reverb, distortion, etc.
Of course, the best thing might be to get the things on your current list and nothing else, then play for a few months and see what you find yourself needing... no need to fill those blanks immediately.