renault, vauxhall 3 series bmw are 4x100 which is same bolt pattern as vw. vauxhall have bigger offset (49mm?? as opposed to about 35 for a golf) so wont sit right. the centre bore will also be too small.(mk2 golf is 57.1mm most 4 stud vauhells are 56.1.
bmw wheels will go on but differences in offset will mean they will stick out about 10mm further than a vw wheel. also 4 stud 3 series wheels are 14 inch anyway(i think)
mx5 wheels would go but again, i think the steels were 14's
renault laguna, megane and espase 4 stud would work on a golf and i dare say they are probably 15's too
seat toledo would fit
if you want to check up on anything wheel related have a look at
www.alloyguide.co.uk its a good site. search for your car and look at the spec for the wheels you need. you can then go through other manufacturers and search for cars with same stud pattern, offset and centre bore. it mainly lists more modern stuff but there's a fair old whack of 90's stuff too. hope that helps