FreeSCOUTcorexy 3D Printer (square aluminum tube frame, scout-tower-like corner nodes, dual-support Z, lots of adjustability to compensate for construction errors)
Thingiverse
6 model
Free
FreeGlock Compensator for airsoft
Thingiverse
FreeDeadshot Glock Race Gun Compensator
Thingiverse
FreeAirsoft m9 compensator with rail
Thingiverse
FreeRobo 3d Auto Bed Leveling (Auto Bed Height Compensation)
Thingiverse
FreeLulzbot TAZ retractable Z-probe auto bed level compensation with G29 Mod
Thingiverse