Klinux v1.2
NE2000, Realtek 8029/8029AS/8039 based cards
(note: Realtek 8019 based cards aren't supported)
Linksys LNE100TX (not tested, but Netgear 10/100 should be OK)
Macroics/MX based, SOHOWare Fast 10/100, CNet 10/100 Pro 120,
and most SMC, and other tulip based Network Cards.
Klinux v1.3
Most 3Com, HP PCLAN, EtherExpress & EtherWorks Network Cards.
Get yourself either a Realtek based, or something you know runs with the tulip drivers.
The Cnet 120 Pro's are a good cheap 10/100 choice.