It has been mentioned that Rock Lee can't use them, but I don't remember Gai using them either. I haven't read the manga.
Unlike Lee, who specialises in taijutsu because he cannot use ninjutsu and genjutsu, Guy is fully capable of using the other two forms of ninja abilities, as he is proficient enough to dispel a high-level genjutsu.
actually he summons this turtle multiple times in the manga
I've seen Gai using the Summoning technique in both manga and anime:
- Rock Lee Vs Sasuke fight
- Gai Vs. Kisame fight
- in Voyage to the Turtle island
Early in the series we see him do turtle summons and dispel genjutsu, and no one makes any explicit or implicit suggestions that taijutsu is the only thing he has competence in. His most powerful abilities were certainly in taijutsu, the gate releases in particular. After approximately the Chunin exams (excluding movies, which are typically non-canon and I'm not familiar with) Gai uses exclusively taijutsu (which is probably why you were thinking he'd never used anything else before), and the only skill any of his opponents ever exhibit caution about is his taijutsu.
Possibly Kishimoto regretted giving Gai other skills. The sudden disappearance of his other skills seems to be a silent, implicit retcon to make the Lee-Guy relationship deeper and more meaningful, or to at least stop said skills from driving a wedge between them in the reader's mind.
Note that we end up seeing Guy's father, aka The Eternal Gennin (not to be confused with a similarly named filler character), and he also has no skills at all beyond the gate releases. We are also shown, during his first meeting with Kakashi, that Guy failed the ninja school entrance exams because he could only do taijutsu. Guy does not become aware of his father's one amazing technique until later, and watches his father sacrifice his life to hold off the entire cadre of the swordsmen of the village hidden in the mists using it. He is thus made into a very strong mirror of Lee—intensely dedicated to perfection of the one ninja skill they can naturally use—deepening their connection.
So while Guy officially has non-taijutsu abilities, they seem to be low-tier, mostly functional abilities that we don't see outside of the early parts of the story.
I did a little bit of digging through multiple posts, official and not so much; to see if this was true for Guy. Sure enough, he has mastered two nature types. These two are made clear to be fire and lightning release.