TOPS was a file sharing platform that came out before AppleShare, but ran on AppleTalk (at least on the Macintosh version.) However, you could run any protocol you wanted over the serial or phonenet cables, so it was technically platform agnostic. They released LocalTalk cards for PCs to be used with DOS and UNIX. FlashTalk was released later on which was an extra fast version of AppleTalk. It used special AppleTalk adapters with separate clocks that enabled for high speed phone net transfers beyond what AppleTalk was capable of at the time.
I used to have a few TOPS boxes for FlashTalk, but I never used them. Eventually gave them away. It was only marginally faster than traditional AppleTalk, and much slower than EtherNet.