Yes. Tons of them. Knightly Orders. Plus in every large realm there were variably formal alliances/leagues of scheming noblemen and landowners, whose power existed in tension with the liege and with other groups. Those wouldn’t exclusively consist of actual knights but they’d be heavily represented & definitely advance common interests
They usually held the same role of military service. Knights receive land from a lord in return for military service so the service of the guild is usually based on a certain region or town (knights of london for example). Guilds would also conduct trade and receive economic protection from whatever lord they fell under. Lords often had multiple guilds and in some cases they did have military uprisings.