Looking for Alternatives to Gra.fo and Protégé Tools

Not sure this is the right chat for that, but is there anyone in this community from https://gra.fo/? 🙂 Any recommendation on similar tools (apart from Protégé). I’ve found this paper (http://www.ef.uns.ac.rs/mis/archive-pdf/2013%20-%20No2/MIS2013-2-4.pdf) but is a bit old.