Is there a list of what books have new race/class options, new monsters, items, etc?

[Odessa333]

This might be a touch newbie here, but I'm book poor and wondering what 5E books have what for content. Like, which books are 'just' modules (just feels wrong here...) and which books gives new classes, races, spells, monsters, items, etc. Is there an easy way to filter this kind of information?

For relevance, if I am to start running games on a virtual table top like roll20, which books do I buy to have the best options both for me and the players?

[Atranen]

They're all kind of mixed; adventures generally have new monsters, settings books have new spells & items, etc.

That said, if you're mostly interested in player options, the first books to look at are the PHB, Xanathar's Guide to Everything, and Tasha's Cauldron of Everything; the latter two are sort of 'rules patch' books which are primarily made up of player options (and reprint player options introduced in other books). That should give you more than enough to play with. If you or your players read about other options you want to try online, then that would be a good time to get the relevant books.

[Khrysaes]

They're all kind of mixed; adventures generally have new monsters, settings books have new spells & items, etc.

That said, if you're mostly interested in player options, the first books to look at are the PHB, Xanathar's Guide to Everything, and Tasha's Cauldron of Everything; the latter two are sort of 'rules patch' books which are primarily made up of player options (and reprint player options introduced in other books). That should give you more than enough to play with. If you or your players read about other options you want to try online, then that would be a good time to get the relevant books.

I would add mordenkainen’s monsters of the multiverse to that list as it adds and/or updates many of the races throughout other books such as volo’s, eberron, witchlight, and others.

[Psyren]

I'd also recommend Fizban's Treasury of Dragons, and Van Richtens Guide to Ravenloft.

A great place to look if you're not sure is a handbook or guide for the class you're thinking of playing - those tend to use the common abbreviations for the various sources. These will also give you the name of the rules element (e.g. subclass, race, feat or spell) so you can look it up, and then decide if you're doing that often enough to want that book.

[swamp_slug]

As the others have indicated, as a newish player there are 4 books you should be looking at: PHB, Xanathar's Guide to Everything, Tasha's Cauldron of Everything and Mordenkainen's Monster's of the Multiverse. As a DM you should also add the DMG and Monster Manual. These 6 books will provide you with a good foundation.

If you feel like adding more books to your collection beyond those then I would recommend checking out the D&D Beyond marketplace. Even if you have no intention of using their service, they do classify books as either sourcebooks or adventures and they give you a detailed list of all the races, subclasses, monsters etc. contained in the book.

[Kane0]

Xanathars and Tashas are the big ones with considerable amounts of extra player-facing content (Artificer, subclasses, feats, alternate class features, spells, magic items, tool and crafting rules, sidekicks, etc). These almost entirely obviate the need to look at the Sword Coast Adventurers Guide apart from a select few offerings that are not reprinted.

Mord's Monsters is like a Monster Manual II but also includes a bunch of player races collated and updated from smatterings found in other books, basically supplanting Volo's Guide but thats a fine book too.

Fizbans and Van Richtens are the smaller ones with a little bit more in the way of player options. Less bang for your buck if you purely want races/subclasses/feats/spells/magic items but also come with some good lore and such if it interests you.

[Myth27]

I think this thread might help you

https://forums.giantitp.com/showthread.php?587020-All-Player-Options-Collected