Racking my memory from a UK perspective (But not limited to UK airlines)
A300
Air Scandic
Dan Air
European Airlines (Belgian ACMI operator in the 1990s that operated UK bases for a while)
Laker
Monarch
Orion Airways
A310
Air Club International
Air Transat
British Air Ferries (wet leased Bulgarian Jes Air aircraft)
Wardair
A330
Airtours
Air Transat
Canada 3000
JMC Airlines
Monarch
MyTravel
Prime
Skyservice
Thomas Cook
TransAer
747
Air Atlanta/Air Atlanta Europe
Air Club International
Air Europe (Operated by Tower Air)
Airtours (Operated by Air New Zealand)
British Airtours
Caledonian
CP Air
European Air Charter
Lion Air/Caribbean Airways (Operating for Airtours Holidays)
Orion Air (Operating for Airtours Holidays) The infamous Flying Pig
Travel City Direct (Actually operated by Air Atlanta, European or XL Airways)
Wardair
767
Air 2000
Airtours
AV8 Air (Not sure if this one ever got off the ground)
Britannia
First Choice Airways
flyGlobespan
Leisure International
Monarch
Thomas Cook
Thomson Airways/Thomsonfly
Virgin Atlantic (Operated by Martinair on the MAN-MCO route as they unexpectedly got permission to fly to JNB and needed the A340 for that)
DC-10
Cal Air
Caledonian
ChallengAir (on behalf of Britannia)
CP Air
Excalibur (Operated by SkyJet, never got their own before they failed)
JMC Airlines
Laker
Laker USA (UK-Florida operation in mid 1990s)
Monarch
Novair
World Airways
MD-11
Monarch (Operated by World Airways the year before A330s arrived)
TriStar
Air Atlanta
Air Ops/ECU Air
Air Scandic (Operated by Aer Turas)
Air Transat
American Trans Air
British Airtours
Caledonian
Classic Airways
Hawaiian Airways
International Airways (Operated by Air Atlanta)
Peach Air (Operated by Air Atlanta/Caledonian if I remember correctly)
Rich International
Worldways Canada
That’s all I can remember for now without “cheating” and looking online!