Just start reading Microsoft Technet and you will find many and more "hidden" registry keys / values. I don't know if there's any list about keys that are not here after clean installation but you will find them after started hacking Windows.
What I do when I need some special functionality/behavior with Windows (or just want to learn more about some well known functionality):
- Try to find about it from google & stackexchange, maybe someone already did that job.
- Try to find alternate ways to do it, if found any then I try to learn from them.
- Find out if any Windows OS can do it, find out how.
- Search registry with regedit, use your imagination here.
- Try to disassemble part of OS that you want to modify/understant better. If failed/stuck, find another route and start over.
- Remember, if it seems that it can't be done you still have many options:
1. Write your own program that a) manipulates existing UI or b) creates new UI or c) extends OS part that you don't like or d) replaces OS part that you dont like.
2. Forgot about it.
Already noted in comments, you should read more about windows internals and ask more specific question after you have some real problems with finding some special values. I think that if you really need full list of reg keys/values then you should make one (at least partially) yourself, as learning exercise.
And as last part, here is few easy lines from logagent.exe:
0000:1188 | CryptUnprotectData..CryptPro
0000:11B4 | tectData....c.r.y.p.t.3.2...d.l.l...E.n.a.b.
0000:11E0 | l.e.N.e.g.o.t.i.a.t.e...S.o.f.t.w.a.r.e.\.M.
0000:120C | i.c.r.o.s.o.f.t.\.W.i.n.d.o.w.s.\.C.u.r.r.e.
0000:1238 | n.t.V.e.r.s.i.o.n.\.I.n.t.e.r.n.e.t. .S.e.t.
0000:1264 | t.i.n.g.s...=.".....r.e.a.l.m... ...,.;.....
0000:1290 | .......N.e.g.o.t.i.a.t.e...B.a.s.i.c. .....
0000:12BC | https://....D.e.l.e.t.e.....N.o.R.e.m.o.v.e.
0000:12E8 | ....F.o.r.c.e.R.e.m.o.v.e...V.a.l...B...D...
0000:1314 | S...................ì...Ø...È...ê¶..¯·..bü..
0000:1340 | I·..d·...·..à·...·..¦·...¹..bü...º..O¾..¶Ü..
0000:136C | .Ý..cÝ..!º..8º..`[..Dº..ú...º..O¾..¶Ü...Ý..
0000:1398 | cÝ...Ï..8º..VÏ..Dº.. [proxy]...:././...1.2.
0000:13C4 | 7...0...0...1...d.o.o.G.....d.r.o.w.s.s.a.P.
0000:13F0 | ....r.e.s.U.....h.t.a.P.....\...SOFTWARE\Mic
0000:141C | rosoft\Windows Media\WMSDK\etacsufbO.... .:.
0000:1448 | ... .?. ...?. .....L.o.a.d.C.r.e.d.e.n.t.i.
0000:1474 | a.l.s...................ì...Ø...È...^..n..5N
0000:14A0 | ·.jC/.ËôWNetRemoveCachedPassword....WNetCach
0000:14CC | ePassword...WNetGetCachedPassword...mpr.dll.
0000:14F8 | PStoreCreateInstance....pstorec.dll.DisableP
0000:1524 | asswordCaching..SOFTWARE\Microsoft\Windows M
0000:1550 | edia\WMSDK..A.c.c.e.s.s.P.e.r.m.i.s.s.i.o.n.
0000:157C | ....A.P.P.I.D.\.{.%.s.}.....A.P.P.I.D.\.%.s.
0000:15A8 | ....L.a.u.n.c.h.P.e.r.m.i.s.s.i.o.n.........
0000:15D4 | ............Ðñ..Áñ...ò...ñ..1ì......Zé..?é..
0000:1600 | ßñ...é..Kê..ßé...í..Xê..iê..Ïò..sê...ê...ë..
0000:162C | 9ë..'ì...(..hò..................ì...Ø...È...
0000:1658 | +...._..÷....ø..3ô..J...a...............¢...
0000:1684 | ....K.......Ý.......à...¹...Z.......äô..#ö..
0000:16B0 | .õ...÷..{ü...ü...ü..ïû..bü..Wü..Wü...ü...ü..
0000:16DC | °û..WSAJoinLeaf.WSARecvFrom.WSARecv.WSAConne
0000:1708 | ct..WSASocketA..WSASendTo...WSASend.WSAIoctl
0000:1734 | ....WSAEnumProtocolsA...ws2_32..U.s.e. .T.r.
0000:1760 | a.n.s.m.i.t.P.a.c.k.e.t.s.......S.o.f.t.w.a.
0000:178C | r.e.\.M.i.c.r.o.s.o.f.t.\.W.i.n.d.o.w.s. .M.
0000:17B8 | e.d.i.a.\.P.l.a.t.f.o.r.m...Æô..._..Õô..Þ...
0000:17E4 | ....+...._..÷...........J...a...............
0000:1810 | ¢.......K.......Ý.......à...¹...Z.......;...
0000:183C | ........................ì...Ø...È...w>.ÍÖfdF
0000:1868 | .Ç6Û¶AÐñS.o.f.t.w.a.r.e.\.M.i.c.r.o.s.o.f.t.
0000:1894 | \.W.i.n.d.o.w.s. .M.e.d.i.a.\.W.M.S.D.K.\.N.
0000:18C0 | A.T.P.o.r.t.M.a.p.p.i.n.g.s.....U.D.P...T.C.
0000:18EC | P...%.x. .%.s. .%.u.....FreeAddrInfoW...GetA
0000:1918 | ddrInfoW....w.s.2._.3.2...d.l.l.....W.i.n.d.
0000:1944 | o.w.s. .M.e.d.i.a. .F.o.r.m.a.t. .S.D.K. .(.
0000:1970 | %.s.)...:.:.....:.:.1...0...0...0...0...?.#.
0000:199C | ....................ì...Ø...È...l...h...d...
0000:19C8 | `[email protected]
Now you got few lines, what to do? If you are lucky values are hardcoded with keys and they can be retrieved from above by looking for record byte sequences and then finding right values. Also you can try to find error messages and their addresses to track down what part of program throws them out (some assembly skills needed but it's not too hard if full reverse engineering/program modification is not requirement).