Bligh Madris is on the upper end of what could be considered for this list as he did play 12 games for the Astros this season when Jose Abreu couldn't figure out how to hit a baseball. However, you may not have noticed him much because, well, he didn't do all that much.
In 30 plate appearances with Houston in 2023, Madris slashed .154/.267/.192 which was somehow even worse than Abreu at his worst. The experiment didn't last very long and Madris made his way back to Triple-A where he has posted a mediocre .756 OPS this season.
Another guy that is pushing it in terms of games played is Cesar Salazar as he appeared in 13 games for Houston this season, although he only had 19 plate appearances. Most of Salazar's playing time came early in the season, although he did have a short stint in June as well. This was when his status as the organization's third catcher meant they needed to have him handy to give breaks at the end of games and Yainer Diaz hadn't solidified his position just yet.
It was probably for the best that Houston sent Salazar back down to Triple-A as his .269 OPS was essentially unplayable. However, he will probably remain an option in the case of emergency or injury to Maldonado or Diaz.
Rylan Bannon is the typical journeyman that can fill in on short notice and not be completely embarrassing, but is not an ideal long-term solution. Bannon made a two game cameo appearance at the end of April in the immediate wake of Chas McCormick going on the injured list.
Predictably, Bannon didn't do much in his two games of work as he was hitless in six plate appearances with three strikeouts. He has also not had the best season in the minors with a .230/.349/.430 line although he has at least hit 16 homers.