Companion plants for Cyclamen
Cyclamen blooms from September through November. It wants part shade and moderate water. The 8 companion pairings below each state why the pairing works.
Blooming before Cyclamen opens

Rhododendron
Shares part shade and moderate water; blooms in late spring, before this one opens; stands well above at 6 ft, a canopy to plant beneath; evergreen, so the bed keeps its shape through winter.

Bergenia
Takes part sun to part shade and moderate water; blooms in mid spring, before this one opens; evergreen, so the bed keeps its shape through winter; taller at 1.5 ft, for the layer behind it.

Summersweet
Shares part shade and moderate to high water; blooms in midsummer, before this one opens; stands well above at 6 ft, a canopy to plant beneath; its white flowers settle the pink.

Goatsbeard
Shares part shade and moderate water; blooms in early summer, before this one opens; taller at 4 ft, for the layer behind it; its white flowers settle the pink.
Taking over as Cyclamen finishes

Camellia
Shares part shade and moderate water; blooms in midwinter, extending the bed's season; stands well above at 6.5 ft, a canopy to plant beneath; evergreen, so the bed keeps its shape through winter.

Hellebore
Shares part shade and moderate water; blooms in late winter, extending the bed's season; evergreen, so the bed keeps its shape through winter; taller at 1.5 ft, for the layer behind it.
Blooming alongside

Northern Sea Oats
Shares part shade and moderate water; opens in midsummer and overlaps into this one's season; taller at 3.5 ft, for the layer behind it; its seed heads stand through winter, for structure and the birds.

Christmas Fern
Takes part shade to full shade and moderate water; evergreen, so the bed keeps its shape through winter; taller at 1.5 ft, for the layer behind it.