These are names of serpents: Dragon, Fáfnir, Mighty Monster, Adder, Nídhöggr, Lindworm, She-Adder, Góinn, Móinn, Grafvitnir, Grábakr, Ófnir, Sváfnir, Hooded One.
Þessi eru orma heiti: dreki, Fáfnir, Jörmungandr, naðr, Níðhöggr, linnr, naðra, Góinn, Móinn, Grafvitnir, Grábakr, Ófnir, Sváfnir, grímr.
This is interesting because of this, from the Grimnismol:
Now am I Othin, | Ygg was I once,
Ere that did they call me Thund;
Vak and Skilfing, | Vofuth and Hroptatyr,
Gaut and Jalk midst the gods;
Ofnir and Svafnir, | and all, methinks,
Are names for none but me.
Óðinn ek nú heiti,
Yggr ek áðan hét,
hétomk Þundr fyrir þat,
Vakr ok Skilfingr,
Váfuðr ok Hroptatýr,
Gautr ok Iálkr með goðom,
Ofnir ok Svafnir,
er ek hygg at orðnir sé
allir af einom mér.
You'll note Svafnir and Ofnir in both lists, with Odin saying in the second that they are names for none but him. Grímr, also, is used for him in another place, though for other things as well. The list definitely starts with serpents, Jörmungandr being Loki's son, the World Serpent that circles Midgard, Níðhöggr being the serpent in the Roaring Cauldron who chews on the roots of Yggdrasil, and Fáfnir being the dwarf in the Volsunga Saga that turns to a dragon from greed. Odin himself, also in the Grimnismol, gives a list:
More serpents there are | beneath the ash
Than an unwise ape would think;
Goin and Moin, | Grafvitnir's sons,
Grabak and Grafvolluth,
Ofnir and Svafnir | shall ever, methinks,
Gnaw at the twigs of the tree.
liggia under aski Yggdrasils
en þat uf hyggi hverr ósviðra apa:
Góinn ok Móinn,
þeir ero Grafvitnis synir,
Grábakr ok Grafvölluðr,
Ofnir ok Svafnir
hygg ek at æ skyli
meiðs kvisto má.
His list has some in common, also including the two he names later as names for himself.
Ofnir means inciter, Svafnir means sleep bringer, or closer. Doesn't take much thought to see them as opposites, Ofnir inciting to action, Svafnir bringing an end to action. Catalyst and Nexus.
It's easy to see these as names for Odin, what's harder is to understand why Odin himself says they are names only for him, and and that they will forever gnaw on the tree. Scholars figure there is likely corruption, that the two names weren't in both lists originally, but this is conjecture, unknown for sure. If he is calling himself a serpent, there may be a mystery in those names.