Besides the 5% hurdle, there's also the smaller 0.5% (of party votes - Zweitstimmen) in Germany that is significant for the many small parties because clearing that number entitles a party to federal funding.

While 29 parties are participating in total, the options I added should be the only ones with a realistic shot. (Some of the other parties with some recognition, such as WerteUnion, are on the ballot in too few states.)

In the last election in 2021, out of these parties, the Tierschutzpartei, dieBasis and DIE PARTEI cleared the hurdle.