stoney-trees

"Hashplants" as they are referred to. Mostly pure indicas as you said. Just indicas great for hash because of all the resin.

yingyangsoup

Both are known for massive trichomes. Indica's have high THC coupled with high CBD so your not getting as much of a trippy head high.

Sativa's are known for high THC and virtually no CBD.

Also, the gene in sativa's that makes them flower begins ALOT earlier than indica's so they get ALOT more time to mature, which also allows more trich production. Sativa's being from the equator experience intense solar power and high UV rays, which in turn produces more trichomes as a defense to it.

It also experiences an equinox all year so they have to somehow incorporate a veg cycle in a 12/12 cycle. They've adapted to growing while flowering, hence the reason they get so big.