Pilgrim can set some fruit alone, but it does better with a partner. Cranberry sets less than 5% fruit from self-pollination alone, making a second genetically distinct variety functionally required for any meaningful harvest. Bumblebees are significantly more effective pollinators than honeybees. It flowers in mid bloom, so a partner has to be flowering at the same time to be any use. Usually grown in USDA zones 3-7.
No single variety stands out as the obvious partner, but that is not a problem here: Searles, Stevens, and McFarlin all bloom close enough to work. Pick whichever your nursery actually carries. Plant cranberry varieties within 10 to 15 feet for reliable bumblebee movement between them. Closer is better in sheltered or low-pollinator sites.
One thing to keep in mind. Cranberry sets less than 5% fruit from self-pollination. A second variety is strongly recommended - expect very little harvest from a solo planting. Bumblebees are far more effective than honeybees at pollinating cranberry flowers.
To put that into practice: at a minimum, two genetically distinct varieties are required. A solo planting will produce very little fruit regardless of care. Better still, three varieties covering early, mid, and late bloom so bumblebees stay active in the bed throughout the full flowering window. If a solo planting produces almost no fruit, adding any second cranberry variety is the fix - cross-pollination is the limiting factor.