An exceptionally interesting "silent" omnibus-style work is The Box Man
Many Western fans searching for "silent omnibus manga work" are actually looking for Jiro Taniguchi’s 1998 masterpiece Distant Neighborhood (published in English by Fanfare/Ponent Mon). While Taniguchi is famous for The Walking Man (also largely silent), Distant Neighborhood is an omnibus of time travel and regret. silent omnibus manga work
While technically a single-volume "gekiga" (literary manga) work rather than a traditional multi-volume omnibus, it functions as a visual anthology of surreal vignettes tied together by a near-wordless journey. Motif: Watch reflection used to connect vignettes