"Any Ideas For a "Neutral" Basing Scheme" Topic

I'm just finishing up some Perry Miniatures' Wars of the Roses and Late C15 Mercenary Infantry figures. I expect that I will be using them for both traditional skirmishes and in fantasy/RPG-type combats. Can anyone please suggest the most "universal" basing scheme – one which will work to some extent in most environments?

For figures I expect to use in both interior and out-of-doors games, I usually leave the base plain and just paint it a very neutral gray-brown color.
Sometimes I'll glue a sand mixture on the base, if I want it to have a little more texture, and then paint and drybrush that with gray-browns.

Similar – I do texture the base with sand mixed into the paint, but find a fairly light earth brown drybrushed with light grey tends to be the best option – doesn't look too out of place on grass, desert, urban or even snow boards.

I've seen perspex used.

I use a sand texture and colour dry brushed but with no other decoration. (Works for pirates on ships and land as well so it's pretty universal.)

Check out your local craft store for a sand art section
There are usually a variety of browns and a grey for a very little cost

If you don't mind painting your sand or you are mixing the sand into the paint anyway---dollar tree stores have bags of white or black sand on sale now

I paint the bases in Desert Sand and then use a grass/sand mix for flock for my Perry WoR figs

Here is my method:

I use Golden Coarse Gel Medium (Available at art stores) to texture the base. You just spread it on and let dry and it gives a great texture.

Then I glue 1 or 2 larger pieces of railroad ballast to it as well to represent rocks. You can do this before the gel dries.

Let dry thoroughly

Paint entire base black

Rough coat of very dark grey

Drybrush with a medium grey

Drybrush again lighter with a light tan

Dab some spots of PVA glue where appropriate and then dip in dark green flock. I do 4 or 5 small tufts one a 1 inch base.

This gives a base that sort of fades into the background on most surfaces. One of my friends called it the mutlicam of bases. Doesn't look realistic on it's own but blends into everything from green to desert to dungeon grey to ships decks without your eye noticing the base is wrong.

Paint base dark brown (I use Raw Umber or Burnt Umber) then on half glue scale gravel (I use medium model railroad ballast). This scale gravel can be scattered or full as you prefer (I do full generally). Finish the scale gravel (I use white ballast so stain Raw Umber then drybrush highlight Medium Gray).

This finish of brown dirt changing to rocky area can represent underground, a bare spot in a field, the edge of a river, edge of a road, mountainous forest floor, ruined city, etc.

I find finishing the base split with two terrain types makes the figures look dynamic, as if crossing from one terrain area to another. (Got this idea from Matakishi's web site.)

Note generally for my own fantasy figures I also finish the brown section. For surface dwellers I put static grass on it. For underground dwellers I put on fine ballast (or white sand), finished the same as the other ballast. But leaving it plain is probably more versatile.

Thank you for all of the very helpful suggestions