Moderator: OpenTTD Developers
While looking through old r/OpenTTD I started seeing a lot of screenshots with really neat scenery and extra buildings.
I've personally never delved to deep into OpenTTD's modding scene, so any help would be greatly appreciated!
I'd suggest looking at the NewGRF List to see links to various forums for each type of NewGRF available, where you can decide for yourself what you'd like to try playing with. Most NewGRF packages can be used with each-other, the few that are restrictive will let you know what they're not compatible with and will usually disable themselves. Personal aesthetics and your own imagination are your only limits.
Base Music Sets: OpenMSX | Scott Joplin Anthology | Traditional Winter Holiday Music | Modern Motion Music
Other Projects: 2CC Trams | Modern Waypoints | Sprite Sandbox & NewGRF Releases | Ideabox | Town Names | Isle of Sodor Scenario | Random Sprite Repository
Misc Topics: My Screenshots | Forgotten NewGRFs | Unfinished Graphics Sets | Stats Shack | RoadTypes?