Oh, there’s plenty of good Trek crossover regarding the cast.
Walter Koenig (Alfred Bester) was killing it during the entire run of B5. Bill Mumy (Lennier) played Starfleet officer Kellen in DS9 S7E08. Andreas Katsulas (G’Kar) played Commander Tomalak in TNG S3E07 / S3E10 / S4E08 / S07E25/26 plus Drennek in ENT S2E22. Who also knocked my socks off was Brad Dourif. He appears in B5 S3 (not going to spoiler anything here). He played Lon Sunder in VOY S2E16 / S2E26 / S3E01.
There’s probably a bunch more actors who worked on both ST and B5, but those mentioned above are the most memorable to me.
Enjoy! It’s one of the few great sci-fi shows out there with incredible wtiting, cast, characters, music and concept art.
I won’t spoiler anything, but buckle up for some insane plot twists, character development and story progression. You think it’s already good now in S2? Oh my, you’re in for a treat come S3 and be ready to have your minds blown in S4.
I wish I could watch it again for the first time, but that’s not possible. But fortunately enough I’m bilingual and only ever watched the German dub. Now, for the first time I’m watching the original English dub and while I’m still in S1, I appreciate the cast even more for their incredible acting. Peter Jurasik most of all with his self-developed accent for Londo.