The Great Pendragon
Formal religions that believe in multiple Gods fall into this category.
Typically adherents will respect and venerate all Gods, of almost all religions. In many cases the will even acknowledge that various Gods are actually the same being: So Apollo is the same as Helios is the same as Mapanos is the same as Bell.
Similarly Mythras is the same as Lugh is the same as Mercury.
However these similarities are not universally agreed (some Pagans state Apollo is the same as Lugh, not Bel for example) and there are often disputes as to what is the appropriate form of worship and characteristics of each God (these have been know to turn violent on occasion).
Typical pagans will identify with and worship only a handful of deities (so a local household or family God, and perhaps one of the major 12 deities) on a regular basis, but will venerate the major deities on their given feast days
Juno (Danu), Vesta, Minerva, Ceres, Diana (Aduinna), Venus,
Mars (Wotan), Mercury(Lugh), Jupiter(Turen,Thor) , Neptune, Vulcan, Apollo (Bel)
Whilst Pagans respect the choice to worship a single God exclusively (such as in a mystery cult) this is considered an extreme, perhaps even fanatical, act: The idea that there is only one God as taught by the Jews and Christians is largely considered radical-atheism, arrogant and / or immoral.
Merlin is the head of the Cymric Pagan religion
Mystis is largely the head of the Roman Pagans in Britain (primarily worshiping Liber aka Bacchus aka Dionysus ) . This sect has attracted many of its followers from across the now defunct Western Empire of Rome, as they flee Frankish invaders, and persecution by an increasingly powerful Christian church.
There is also frequent talk of a powerful Mythras sect and even an Isis sect, but these two groups are far more secretive and so wield less power ( in public at least!). The temple of Jupiter in London still stands, and has painted or sculptural representations of all the main Roman Gods.