There's a couple of selection scripts on AEScripts.com. I'm sure they could be modified easily to provide that functionality. Also check AEnhancers.com, perhaps there's some gem hidden in one of the old discussions there.
Thanks (as ever) sir. Will update/recommend if I find anything
Short answer: No.
Longer answer: Try organizing your layers into label groups using the available 16 colors. You can then select all label groups by right clicking on the layer group color.
You can also use shift + click to select multiple layers. Scrolling down using the scroll bar on the far right is very quick.
Don't be afraid to pre-compose. I've worked on many projects with hundreds of layers, but most of them were in pre-comps to make things easy to switch around.
Don't make your sequences too long. There's a real tendency for new editors and new AE artists to try and put a whole program in a single timeline. That's a very inefficient way to work. There's never been a feature film cut as a single reel. There's no reason at all to have an AE timeline 10 or twenty minutes long. Limit your sequences to one 'thought' or one bit of business. Nobody is that good of an editor. Keep your sequences short, then either edit them in a NLE or combine the comps in a main comp in AE. That way, if one part of a sequence needs a little more work you have a smaller amount of footage to shift around. Most of my AE timelines are no more than 1 or two shots in a single comp. Most of my AE sequences are no longer than 10 or 15 seconds. Even my dynamic text animations or my 2.5D slide shows are cut up into sections so I can efficiently make edits as the client or the project evolves. I can't recall any sequence being more than a paragraph of dialogue.