If it's not on my list, I typically want to fill in 2g's from pairings with dragons that have come out in the last few years that I have missed, like xenos, aeon, gemshard, galvanic etc. This gives me more reason to collect CB's of my own.
Gold:
F.hellfire [x] - completed 3g
M.water [x] - completed 3g
F.moonstone [x] - completed 3g
M.sweetling [ ] - have 3g gold
F.blue banded [ ] - have 2g blue banded
F.white [ ] - have 3g white
F.green [ ] - have 3g green
M.sunsong [x] - completed 3g
M.nhiostrife [x] - completed 3g
*F.gold shimmer [ ] - have 2g shimmer
F.arcana [x] - completed 3g
M.arcana [ ] - have 2g arcana
M.marrow [x] - completed 3g
M.omen [x] - completed 3g
F.omen [ ] - have 2g omen
F.grave [x] - completed 3g
F.kohraki [ ] - have 2g gold
*F.bronze tinsel [x] - completed 3g
M.thalassa xeno [ ] - have 2g gold egg
F.black zyu [ ] - have 2g zyu
M.black zyu [ ] - have 2g zyu
F.undine [ ] - have 2g undine
F.black [x] - completed 3g
F.black truffle [ ] - have 2g truffle
M.ice [ ] - have two 2g gold
F.aria [x] - (thuwed) completed 3g
M.hellfire [ ] - have 2g gold and hellfire egg
F.bronze shimmer [ ] - have 2g shimmer
Silver
F.waterhorse [x] - completed 3g
F.vine [x] - completed 3g
M.royal crimson [x] - completed 3g
M.flamingo [x] - completed 3g
M.frill [x] - completed 3g
M.spring [ ] - have 2g spring
M.silver [ ] - have 2g and 3g female
F.sunsong [ ] - have 3g silver
F.grey [ ] - have 2g grey
F.black [x] - completed 3g
F.swallowtail [ ] - have 2g swallowtail
F.hellfire [ ] - have 2g silver
F.horse [ ] - have 2g horse
M.floret [ ] - have 3g floret
F.white [ ] - have 2g white
F.red [ ] - have 2g red
F.red copper [ ] - have 3g copper
F.moonstone [ ] - have 2g and 3g moonstone
M.red gemshard [ ] - have 2g gemshard
M.thalassa xeno [x] - have 2 2g xeno's and 1 2g silver
*F.silver shimmer [ ] - have 2g silver
*M.bronze shimmer [ ] - have 2g shimmer
F.witchlight [ ] - have 2g witchlight
F.omen [ ] - have 2g omen
M.royal blue [ ] - have 4g royal blue
F.shadow walker [ ] - have 3g silver
*M.silver tinsel [ ] - have 2g tinsel
*F.silver tinsel [ ] - have 2g silver
M.aeon [x] - completed 3g
M.galvanic [ ] - have 2g galvanic