These bar clamps could be used to hold a threaded assembly with a shaft seized inside it, their length provides valuable additional leverage.

IRWIN QUICK-GRIP Light-Duty (63kg) Mini (300mm) Trigger Clamp, Twin Pack, T54122EL7
5.0

WORKPRO 4-Piece Clamps for Woodworking, 150 mm x2 & 120 mm x2, One-Handed Clamp/Spreader, Wood Clamps Set, Light-Duty Quick-Change F Clamp 23/68 kg
5.0