as written by design they should be compatible to gpib standards but companies sometimes love to make their own sauce / some variantions, commands, time outs, delays
the well known are Prologix, Keysight and NI
the HP / Agilent model was cloned to no ends, the newest Keysight models seem ok for now, Ni had some clones at some point
you have forks like arduino based ones, or other mcu to mostly mimick Prologix adapters, they can have their quircks too
and yes you had many problems with isa pci cards - drivers where a nuisance and still are, same for softwares ... you have to did a lot to find old gen stuff