A tweak of Illuvis's
[link]that I saw from ~
Len1's tweak of his params

Had to give them a go!
BG is a render of the following M3D, flipped vertical!
Mandelbulb 1.8.2
Mandelbulb3Dv18{
b.....s/...C2...61....U...UTH4ZPvNv1.HDPpUlq2i.khrm4tqInpy1Bky/0SnMszkIda9XtRx.k
................................AAMC/XsCJ/2........Y./.........E........y.2...wD
...Uz.....kW.....MU0/....6kd4...00....E0......CEl6kVnhiD/.kNfQlD...G2dkpXm1....U
./EnAnQD12../2Uj/4C8S4WrzYzUKxzpiw.EcrcbX3WByz9............u1....y1...sD...../..
.w1...mDNlPWjrGCLvPjcPnwmpesyS958NNeh/ij/MAXErEDavn01SbAUVDVygnMZR8EL.ij2FQA4VQG
KvXPiAbYnp/tyGZ6ejy.wrhD......YkD.............kD.2....sD2.E.....................
.............oAnAt1...sD....z.Lvf6.2ijW.kuy80.pvf6.wjjW.E0z80.Hwf6kNfQlDC....UA.
.....AQxcz1.....2.kz.2YDsUEb..6......k2...EA....Q/....5...k.....O/...cFB...UiPDV
...U.OenA5oddefDom8ZsQJJe/..2c..WDSu..UPAI91pRxj4odIWOorVy1.JzHmWnv4.1./8..iwV3.
.Ak5eP./cz1.2RiGMQZhz.UfzHx6d2yD.AV0..bju0..R8Zc4xRkzu/8YqFpt/zj.czYfTLkRz1.Ic..
B87c..kYEkti4xwD.W.Ehl2Ilz1.WRvgcbtszG.78ozJ7l1..kRiZZj/Wy98cv57wJ.2./EXNC7WBInD
2.W3yj3R00..WbtzJfMcz0kO0xKvVm.E..VFVEzwqw9..MW6O..U.06UVGlOW/3..1Ak.r3AKFpG.cgm
8fQg2hIGx.UaOeda4uIG3d1..06U.iXJbxpD..6U.0ciUl07I.UaOedaOV4G4/2..06U.yLQkoG7..6U
.0MWvBIEq.UdaOed..UDp6UAee0Pex2OIJZJKhIJszbDp6UAnJbMh24RjpKOX/mQttKMkBLNUIrQYtWO
E....E..........zzzzz1......HZaPN/kQI/5S.............................c..........
...................wz...........................................................
...................................wz...........................................
.....................I.....3....1....wJEh3aSdtqN0x4SHBJFm.......................
.Qk0...........................kBnAnAnAngz1........wz...........................
................................................................................
................................/....E/...U/....B3aPYZrEjJrQdt4..A4.............
........................................Y.2........B./........zD..........2.....
...../..........................................................................
..........................................E.....4....A....UFjl4NdtqNUYYPo/0IjR5.
.....................c..6............................/.......E1k..........2.....
...wz...........................................................................
...................Illuvis/cmdrchaos............................}
Great job!
But there are formulas I prefer, like the AmazingBox+Octahedron which I stuck to for months, or the more recent SierpHilbert+Reciprocal(s) which wasn't my idea but was a find by MJB.
My most successful ones are recently made with:
_Folding2 to have a symmetry
SierpHilbert with increasing iterations to have more and more details
_ReciprocalX and ReciprocalZ to smooth things
InvCylindrical to have the beautiful curves
In the most complicate ones I could use all of the above (and no more than those ones), but sometimes I can even skip a couple of them.