Most airsoft pistols will fit a suppressor/tracer of 11mm (14mm is for rifles)
But you'll have to make sure the pistol has a threaded barrel as some don't.
Look for makes including WE, KWC, KWA, KJWorks for gas operated pistols
Look for makes including Umarex, Cyma, JG for electric pistols or rifles
For pistols you'll have to spend over £60 to get anything half decent in electric (AEP)
For rifles you'll have to spend £80 and up (AEG)
bbguns4less is not the place to get anything good...
Try Patrolbase, BespokeAirsoft or AirsoftWorld