I think Frozen should be added. There are two arguments:
1. It is in the same limited way GPU mineable as any other Quark clone
2. The GPU mining for Quark / Frozen is currently very limited:
- There is currently only one GPU miner available ("Smelter": a closed source project which supports only a few GPUs and takes 10% of the profit)
- Smelter is not supporting pool mining
- At the current difficulties of Frozen the GPU miners report that they find no more blocks by solo mining => GPU mining impossible now
- Even if the difficulty is low so that solo mining of Quark / Frozen with GPUs work it has shown not have give that big gain compared to CPU mining