I really like growing from seed, including wildflowers, with widely varying results ranging from lots of plants (including self-seeding for years, 1 packet of seeds, plants for life) to zero plants. Here are my hits and misses.
Borage - easy to grow, easy to collect seeds, also self-seeds
Corncockle - reasonable number of plants
Cornflower - reasonably easy except for the slug problem
Field / Red / Corn Poppy - impossible to grow from seed
Field scabious - few plants still flowering years later
Forget-Me-Not - self-seeds like mad, always seedlings about, don't know about collecting seeds - not necessary
Foxglove - easy
Globe thistle - easy and strong self-seeder
Greater knapweed - impossible to grow from seed
Green alkanet - self-seeds like mad, always seedlings about, don't know about collecting seeds - not necessary
Lesser knapweed - easy and not eaten by slugs, keen self-seeder and loved by bees
Marsh Mallow - I got 4 plants from a packet of seeds, guess that's ok, 1 has flowers (July), will see how the others do
Meadow Cranesbill - challenging, got 6 plants from a seed packet, two (or threee?) years to flower, don't know self-seeding
Melancholy Thistle - extremely challenging, if only because the slugs eat it voraciously, but reasonable germination, trying again
Monarda - extremely challenging, if only because the slugs eat it voraciously, but reasonable germination, no plants extant third year (blooming wasn't until 2nd year) as the slugs ate them completely so don't think it's worth trying again - unless I keep in a pot
Ox-eye Daisy - wildly successful and strong self-seeder
Scotch Thistle - only got 1 resulting plant but when it's huge, that's all you need
Self-heal - reasonable number of plants, my first year growing from seed so don't know the self-seeding habits
Teasel - easy, lots of plants and strongly self-seeds
Viper's Bugloss - difficult, only 1 resulting plant but few years had the odd one self-seeded appear, whereas cultivar Blue Bedder, reasonably easy