Soul Link

A list of anime containing ecchi elements, but are not tagged as ecchi by MAL. While the ecchi content may not be as prevalent or extreme as officially-tagged ecchi titles, there is still enough to be of interest to fans of the ecchi genre. Many of these register at least 1.5/3 stars on AniDB's "tag-weighting" system for ecchi.
Conversely, those who don't care for ecchi may wish to use this stack for cautionary purposes, as these titles may contain things like pantyshots, revealing outfits, incestuous overtones, oversized/jiggling breasts, swimsuit/lingerie moments, extended bath/shower scenes, lewd dream/fantasy sequences, innuendo, or general fanservice in an otherwise serious/"respectable" show.
Only the first seasons of franchises are listed. Some titles may (eventually) have additional details explaining why I've placed them on the list.

Part 1: https://myanimelist.net/stacks/24838
Part 2: https://myanimelist.net/stacks/26746

NOT an exhaustive list. 50 TV anime adapting visual novels/ eroge with a male protagonist, usually with romance or a harem. Went for a generic sample, excluded series too exceptional/ distinct (Higurashi, Fate/Stay Night, ef: A Tale of Memories., etc.). 5k members minimum.

Anime adaptions that are based on Visual Novels, and the Visual Novels have been translated to English. Also Eroge, Bishoujo Game/Galge, Otome Game, Nakige/Nukige tag.

(PART 2) https://myanimelist.net/stacks/50570
(PART 3) https://myanimelist.net/stacks/51424

Ero-Anime adapted from Visual Novels with English release
https://myanimelist.net/stacks/50524
Manga adaptions based on Visual Novels with English release
https://myanimelist.net/stacks/50508

Mecha anime based on visual novels.