New Vegas added Elder Scrolls-style harvesting of resources like plants etc. to the game that I really like.
An idea I had was to make Fallout 3 have some of that. Obviously, we can't add stuff like broc flowers agave xander root whatever to the Capital Wasteland, but there are some things we could do. I have all the resources to make the following work:
Ant/Mirelurk/Deathclaw egg piles turned into harvestable things rather than containers that visibly have the eggs disappear when you harvest them
turning static Fallout 3 cave fungus into pickable cave fungus like in new vegas and new vegas DLC
also there's a mod I didn't make but I saw called some food mod, it's free to use and it adds Mutfruit and Crunchy Mutfruit pickable plants like in NV, which we could distribute in like Oasis or something although it might be weird
Any of those sound interesting?