cmd_auto_invisible_layer - When adding a new layer you it doesn't make it visible in every scene.
ene_texturepositioning - Quickly change texture orientation with Shortcut
Mirror - Self explanatory
PutOnLayer_sortname - Easily cleanup someones messy layering in a model
SectionCutFace - To create sections that you can then draw on
tt_selection_toys - Select only face/edges/hidden lines etc...
su_solarnorth - Change north position
RoundCorner - Self explanatory
TIG-weld - Weld edges together into single edges
SU Podium Browser - For models / materials etc...
1001bit_freeware - I only really use the fillet tool on this. But it's really useful.