Just to say I found anthologies very useful as places to explore and attempt to inhabit when I began seriously writing poetry. (Donald M Allen, The New American Poetry [Grove Press, 1960], Robert Creeley & Donald Allen, The New Writing in the USA [Penguin Books, 1967] and Ron Padgett & David Shapiro, An Anthology of New York Poets [Vintage, 1970) if you're interested.) Find an anthology that really interests and excites you, and try dwelling inside its various rooms.
- Jeff Hilson, The Reality Street Book of Sonnets (Reality Street, 2008) — in fact including a wide range of late modernist anglophone poets, but selection dominated by British Innovative Poets, with a wide selection of amazingly inventive pieces
- Carrie Etter, Infinite Different: Other poetries by U.K. Women Poets (Shearsman, 2010)
- Chris Goode, Better Than Language: An anthology of new modernist poetries (ganzfeld, 2011) — very informative introduction
- Harriet Tarlo, The Ground Aslant: An anthology of radical landscape poetry (Shearsman, 2011)
- Tom Chivers, Adventures in Form: A compendium of poetic forms, rules & constraints (Penned in the Margins, 2012) — organised by how the poems were written (& "rules" is just jokey, don't worry)
- Nathan Hamilton, Dear World & Everyone in It: New Poetry in the UK (Bloodaxe, 2013) — wonderfully messy anthology, which is a strong virtue (tho' I can't bear to read its introduction)
- Sarah Crewe and Sophie Mayer, Glitter Is a Gender (Contraband, 2014) — "we're really bored with reading heteronormative, cis mainstream poetic perspectives on gender. We want to hear more of the other" Highly enjoyable!
- Emily Critchley, Out of Everywhere 2: Linguistically innovative poetry by women in north america & the UK (Reality Street, 2015) — siting and citing contemporary women writers 20 years after Maggie O'Sullivan's Out of Everywhere: Linguistically innovative poetry by women in north america & the UK (Reality Street, 1996)
- James Byrne and Robert Sheppard, Atlantic Drift: An Anthology of Poetry and Poetics (Arc Publications and Edge Hill University Press, 2017) — interested in the current state of the dialogue between British and American innovative poetry and poetics
- Isabel Waidner, Liberating the Canon: An anthology of innovative literature (Dostoyevsky Wannabe, 2018) — "If there were a literary avant-garde that were relevant now, it would be what the queers and their allies are doing, at the intersections, across disciplines. This avant-garde would be inclusive, racially and culturally diverse, migrants galore, predominately but not exclusively working-class, transdisciplinary, (gender)queer and politically clued up (left)." Though mainly writing prose.
- Ágnes Lehòczky and J T Welsch, Wretched Strangers: Borders Movement Homes (Boiler House Press, 2018) — "brings together innovative writing from around the globe, celebrating the irreducible diversity such work brings to 'British' poetry", mainly from poets resident in the UK (or Ireland) but not born there. A superb anthology
- ℵ Rebecca Tamás, So Mayer & Sarah Shin, Spells: 21st Century Occult Poetry (Ignota, 2018) — "thirty-six contemporary voices exploring the territory where justice, selfhood and the imagination meet the transformative power of the occult. These poems unmake the world around them, so that it might be remade anew." Powerful.
- John Goodby and Lyndon Davies, The Edge of Necessary: An Anthology of Welsh Innovative Poetry 1966-2018 (Boiled String Press and Aquifer Books, 2018) — with a range of writers within, coming to or coming from Wales — a supremely enjoyable and exciting anthology!
If you want to investigate anthologies containing innovative British poetry further, you will find an archived page useful: List of Anthologies, Literary Histories & Critical Texts (1948—2011).
I'll end with the definition used in The Edge of Necessary (Introduction, p 15) to define the area the editors were interested in: "modernist-influenced poetry written in English — that is, of the kind variously labelled alternative, neo-modernist, experimental, avant-garde or innovative (no singe term is adequate, and this anthology [read "website" — tho I also think innovation is a vital artistic element] simply uses the one its editors feel is the least disputable). By 'innovative' we mean the kind of poetry which registers the lessons of Modernism and contemporary formal and linguistic experiment, along with the more radical twentieth and twenty-first century discoveries in psychology, philosophy and the physical sciences. Such poetry is distinct from the even more misleadingly-named 'mainstream' poetry, which tends to work within a narrowly conceived rationalist empirical tradition, built within a vision of the world as comprised of objects on the one hand and a more or less unitary speaking and observing self on the other, each firmly grounded and in its place." Goodby and Davies then go on to deal with how this poetry encounters varying definitions of "Welshness". What those of us who are British but not Welsh, Irish, Scottish (or Cornish!) need is to encounter that place we are in, and how we can make sense of the poisoned chalice of Englishness. Dash it to the floor, maybe.