| Alfonso Conspiracy | 2018 | — | — |
| Aliases | April 2010 | — | — |
| Alien Sex Fiend | 1982 | — | — |
| Alister Malcolm | 13 March 2024 | — | — |
| All About Eve | 1984 | 2004 | — |
| All Consumed | 2012 | — | — |
| All Living Fear | 1992 | — | — |
| All Out Attack | 2011 | — | — |
| All Saints | 1993 | 2022 | — |
| Allo Darlin’ | 2008 | 11 December 2016 | — |
| Alloy Mental | 2005 | — | — |
| Almeida | 2007 | — | — |
| Alpinestars | 1999 | 2003 | — |
| ALT BLK ERA | 1 November 2021 | — | — |
| Altered Images | 1979 | 1983 | — |
| Alternative | 1979 | 1986 | — |
| Alternative TV | 1976 | 1998 | — |
| Alt‐J | 2007 | — | English indie‐rock band |
| AlunaGeorge | 2009 | — | — |
| Alvin Purple | 2008 | — | — |
| Amaranthine Trampler | 2004 | — | — |
| Amber Run | September 2012 | — | — |
| Amen Corner | 1966 | 1970 | 60s British Group |
| Amenophis | 1993 | 1995 | — |
| Amnesia | 1988 | — | — |
| Amok | 2004 | — | — |
| Amp | 1992 | — | — |
| Amplifier | 1999 | — | British alternative/prog/space rock band |
| Anaal Nathrakh | 1999 | — | British extreme metal band |
| Anarka & Poppy | 1982 | 1984 | — |
| Anathema | 1990 | 2020 | British alternative / progressive rock band |
| Anathematize | June 2006 | August 2008 | — |
| Anavae | 1 September 2011 | — | — |
| Ancient Grease | 1967 | 1970 | — |
| And Also the Trees | 1979 | — | — |
| And Now the Owls Are Smiling | 2016 | — | — |
| And So I Watch You From Afar | 2005 | — | — |
| Anderson Bruford Wakeman Howe | 1988 | 1990 | — |
| Androids of Mu | 1980 | 1983 | — |
| Andy Scott’s Sweet | 1985 | — | — |
| Anesmwythder | 2014 | — | — |
| Angel Nation | 2011 | — | previously known as EnkElination |
| Angel Witch | 1977 | — | — |
| Angelic Upstarts | 1977 | — | — |
| Angtoria | July 2004 | — | — |
| Anihilated | 1982 | — | — |
| Animal Noise | 20 April 2010 | — | — |
| Animals That Swim | 1989 | — | — |
| Annihilist | 2007 | — | — |
| Annotations of an Autopsy | 2006 | — | — |
| Annoyance | 1990 | — | — |
| ANOHNI and the Johnsons | 1995 | — | — |
| Anorexic Dread | 1983 | 1985 | — |
| Another Sky | 1 January 2017 | — | — |
| Another Sunny Day | 1987 | 1992 | — |
| Anoxia | 2006 | 2009 | — |
| Ante-Inferno | 2017 | 31 August 2025 | — |
| Anterior | 2003 | — | — |
| Anthrax | 1980 | — | — |
| Anti Vigilante | 2004 | — | — |
| Anti-Clone | 2011 | — | — |
| Anti-Nowhere League | 1979 | — | — |
| Anti-Pasti | 1978 | 2022 | — |
| Anti-System | 1981 | — | — |
| Antidote | 1986 | 1986 | — |
| Antimatter | 1998 | — | English band |
| Antisocial | 1981 | 1984 | — |
| Antre | 2017 | — | — |
| Any Trouble | 1978 | — | — |
| AOS3 | 1990 | — | — |
| Apache Viking | August 2009 | — | — |
| Apartment 26 | 1999 | 2004 | — |
| Aphonic Threnody | 2012 | — | — |
| Apollo 440 | 1990 | — | electronic rock band |
| Apologies, I Have None | 2004 | — | — |
| Apparition | 2004 | — | — |
| Appliance | 1996 | 2003 | — |
| April’s in Paris | 2001 | 2001 | — |
| Arab Strap | 1995 | — | Scottish indie rock band |
| Aragorn | August 1978 | July 1983 | — |
| Arbitrater | 1986 | — | — |
| Arcadia | 1985 | 1986 | — |
| Archaicus | 2001 | 2012 | — |
| Archie Caine | 2021 | — | — |
| Architects | 2004 | — | British metal band |
| Archive | 1994 | — | UK trip‐hop/post‐rock band |
| Arctic Monkeys | 2002 | — | — |
| Ardentjohn | 1 November 2005 | — | — |
| Arena | 1995 | — | British prog rock band |
| Argent | 1969 | — | — |
| Arkarna | 1994 | — | — |
| Arkdown | 17 August 2015 | — | — |
| Armitage Shanks | 1991 | — | — |
| Arrant Saudade | 2015 | — | — |
| Arrogant Destruktor | 2012 | — | — |
| Art & Language | 1967 | — | — |
| Art Bears | 1978 | 1981 | — |
| Art Brut | 2003 | — | — |
| Art of Noise | 1983 | 2000 | — |
| Artery | 1979 | 1985 | — |