AddedCompat: Alchemy by SkylordJoel
AddedCompat revolves mostly around alchemy, a spiritual successor to Equivalent Exchange 3 for 1.6.2. Currently, IC2 is supported but plans to support more mods exist.
Compact Solar Arrays by cpw
Compact Solar Arrays, an Industrial Craft 2 mod that adds in three new Solar Panel type blocks: Solar Arrays. Solar Arrays condense 8 (Low Voltage), 64 (Medium Voltage) or 512 (High Voltage) Industrial Craft 2 solar panels into a single block. This significantly reduces the CPU impact of large amounts of Solar Energy gathering so is a common server enhancement.
CompactWindmills by Aroma1997, Schillaa
This mod/addon for IndustrialCraft2 adds CompactWindmills to the game. They are basically More Windmills within one Block: Availible in ELV(8EU/t), LV(32EU/t), MV(128EU/t), HV(512EU/t) and EV(2048EU/t). They save CPU if used in big power plants.
DenPipes by denoflionsx
DenPipes is a small addon for Buildcraft that implements various pipes that aid in making builds smarter and more compact
addon opensource tech
Extra Bees by Binnie
Extra Bees is an addon for the Forestry Mod, by SirSengir, that adds 72 new species of bee and 37 new honey combs, most which can be centrifuged to give products from vanilla Minecraft, Forestry and other forge mods such as IndustrialCraft 2 and Railcraft. It also adds machine to manipulate and sort your bees.
FMPIntegration by wasliebob
This mod adds microparts for all blocks ingame
cosmetic opensource addon
GregTech by Gregorius Techneticies
This Addon adds the awesome Technology of GregTech-Intergalactical to your World! Fusionreactors, Lightningrods and many other Technologies and convenient Recipes are added by this Addon, if you let them enabled in the allmighty Config, of course