Try this list of classic English garden perennials with pink flowers. Many of these will be found in other colors too, so I’ve tried to give the specific cultivar or variety that is pink. You may find others.

Pink perennials that bloom in summer

Monarda didyma or Bee Balm.‘Croftway Pink’ has soft pink blooms.
Must have a sunny spot and moist soil. When it dries out, it increases the chance of getting powdery mildew. Can be invasive, so deadhead before the seeds dry out and fall.

Sidalcea -‘Sussex Beauty’, ‘Oberon’, ‘Loveliness’, and ‘Puck’ all have pink flowers. Similar to hollyhocks but shorter. Full sun.

Malva alcea or Hollyhock Mallow
Has saucer shaped flowers in rose pink. Full sun. Can be invasive, so deadhead before the seeds fall.

Lupinus –Lupin ‘The Chatelaine’ is one of many pink flowered lupins.
Prefers a sunny spot, well-drained slightly alkaline soil. Re-seeds, but not invasively, and does not always come true to seed.

Phlox paniculata ‘Eva Cullum’, ‘Bright Eyes’ and ‘Pinafore Pink’ all have lovely pink flowers. Full sun, but keep soil moist to guard against powdery mildew.

Astrantia major likes moist, shady spots and lots of compost.

Heucherella tiarelloides or Foamy Bells - ‘Bridget Bloom’ flowers up to two months.

Geranium endressi ‘Wargrave Pink’ is the most popular cultivar and will grow well in sun or partial shade.

Physostegia virginiana Vivid – or Obedient plant.
Has dark lilac pink flowers on hinges that can be placed into position, hence its name.
Best in a sunny spot with fertile, moist but well-drained soil.

Lychnis ‘Flos-jovis’ or Flower of Love, has deep rose pink flowers with grey foliage. Prefers sun and well-drained soil.

Dianthus or Pinks. There are many pink varieties: try’Bath’s Pink’,’Flore-plena’, ‘Pink Feather’, “Essex Witch’All are scented or very scented and enjoy a sunny spot with well drained soil.

Pink perennials that bloom in autumn

Sedum spectabile or showy stonecrop. ‘Carmen’ Has fleshy grey green leaves with bright rose pink flower heads loved by butterflies and bees. Full sun and prefers fertile well-drained soil, although it will grow in most soils.

Aster novae-angliae ‘Harrington’s pink’ has daisy-like flowers that are pink with yellow centers. Pinch back in early July to reduce the need for staking, as this can get 3-4 feet tall.

Aster novi-belgi ‘Orlando’ is smaller than novae-angliae but also has pink flowers with yellow centers.

Both prefer a sunny spot, fertile soil and well-drained soil although they don’t like to dry out completely.