How much 4e mechanics already exists in OGL products?

[Voadam]

I'm curious how many of the 4e mechanics that we are aware of already exist or are close to similar existing mechanics in OGL products.

Unearthed Arcana has action points, options for PCs rolling all dice (so PCs can make magical attacks against enemies' save DCs), reserve points for self healing between fights, variant skill mechanics, and other optional rules.

Iron Heroes and Book of Iron Might have some sort of skill challenge type stuff.

E.N. Publishing's The Fantastic Science sourcebook has a class variant, the technologist savant I believe it is called, with 3e warlock style at will magic-type abilities.

Mastering Iron Heroes and Foe Factory Modern have quick villain design systems using different rules from PCs.

Stretching a bit per encounter abilities are effectively similar to dragon breath recharge times from the srd or the UA recharge magic variant if the fight is short enough. Similarly a couple 3.5 psionic abilities such as psionic focus and certain soulknife abilities are fairly tough to recharge during combat making these in effect 1/encounter type abilities with specific recharge triggers.

Warlords I haven't checked out enough to figure out if there are similar OGL variants.

What else of what we have seen for 4e does and does not translate mechanically from existing OGC?

 

[Alzrius]

The big one would be Monte Cook's The Book of Experimental Might, which lists reclassifies spell levels from 1-20, so that they match character levels. It also has variable class features, including a cleric feature that allows one being healed to spend an action to activate the healing, rather than the cleric. Finally, it also simplifies and combines Move Silently and Hide into a single Sneak skill (though oddly, it doesn't do the same for Spot and Listen).