Purpleheart Armory is a great source for HEMA equipment of all kinds. The site has enough equipment to be a bit intimidating - if you're looking for practice swords the longsword page is what you want. The VB techniques feder and Italian feder both get good reviews and are inexpensive.
HEMA Supplies has Regenyei feders for longswords and many other weapons, as well as Sparring Gloves and a few other items.
There's a lot of bad interpretation out there, but there are a few people putting together worthwhile resources. The Illustrated Ringeck on facebook is a pretty nice set of modern photos that cover Liechtenauer longsword. Because facebook is a terrible place for information you'll have to scroll way back to start at the beginning.