The show's about an anime school club, and it's constantly using references as a part of it's context, not for comedy purposes.

at least i think they're not meant to be funny, since the show isn't

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Not exactly excessive in this one, but they do pop up here and there, be them from Macross or doraemon.

Keep your eyes peeled, keep your eyes peeled, and you might be able to spot the plethora of building signs, books, cardboard cutouts, and sometimes characters from other shows everywhere.

The show features a cast of Otaku's, and uses references constantly for comedy as a parody.

Gintama is strongly dependant on references, it uses them mainly by either ridiculing them for comedy purposes, or randomly mentioning them at certain points to make a point.

Although not very common in this show, it uses references to famous shows for comedy purposes.

It references a few earlier works by studio Gainax, such as NGE and Gunbusters.

Multiple characters from different shows such as Sayonara Zetsubou Sensei or A Certain Magical Index make a cameo appearance or are referenced during skets.

it's a slice of life comedy full of parodies and references to other animes an the otaku culture.

'I see Haruhi!'

Not for any other shows, but Mix includes many references to itself, and it's author, often breaking the 4th wall in the process.

the show constantly pokes fun at big anime titles from the last decade.

Poputepipikku is filled with absurdity and references from differnet titles and mediums from western or eastern franchises. be it simply quoting certain lines, to blantantly showing games such as Skyrim or Pokemon, or recreating scenes in a ridiculous manner. DANK 4 LYF.

similar to Gintama in style, it uses references to other animes for comedic purposes.

Given that it takes place in a Bookstore that sells manga, the show often references other titles.