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Now is a great time to support the UK museums you love with donations, pre-booked tickets (if available) or buying from their online shops. Can we start a thread below of some great online museum gift shops?
To start, the @MuseumofLondon shop has an excellent book selection and some really lovely gifts! The suffragette merch is 
https://museumoflondonshop.co.uk
https://museumoflondonshop.co.uk
The @CharlestonTrust shop is next level Bloomsbury heaven! I’m eyeing up all the textiles, obviously https://shop.charleston.org.uk
So many brilliant replies to this, thank you all! I'm going to collate them into the thread below with links to make it easier for people to follow. 
Got a couple of suggestions for the brilliant
@vagina_museum shop which can be found here: https://vaginamuseumshop.co.uk
@vagina_museum shop which can be found here: https://vaginamuseumshop.co.uk
Of course the @V_and_A has an amazing online shop! https://www.vam.ac.uk/shop/ (The stuff from the recent Kimono exhibition looks particularly great)
Thanks to @fashademic for recommending the Serpentine and Whitechapel Gallery shops! Find them here: https://shop.serpentinegalleries.org/ and here: https://shop.whitechapelgallery.org/
The moquette range at the @ltmuseum is truly a dream! More here: https://www.ltmuseumshop.co.uk/ https://twitter.com/f_osis/status/1322827010142543872?s=20
No dedicated online shop but sounds like it is worth messaging @CoffinWorks to order! (And I'm definitely adding it to my wish list for a post-lockdown visit) https://twitter.com/Conflict_arch/status/1322830758675886081?s=20
The @NatGalleriesSco shops really are lovely, perfect for Christmas shopping: https://twitter.com/JoanKeating2/status/1322831844979736576?s=20
Thanks for this suggestion @PrincessHamira, love the lace range! https://www.devonmuseums.net/RAMMshop/ https://twitter.com/PrincessHamira/status/1322832187801145345?s=20
https://paisleythreadmill.co.uk/shop/ Love the bobbin keyrings here! https://twitter.com/pjmck/status/1322832454554714119?s=20
Great suggestion for fashion fans, lovely books and stationary. As well as some Merchant & Mills products! https://ftmlondon.digitickets.co.uk/category/26371 https://twitter.com/mydog_ringo/status/1322832556522307585?s=20
Thanks for these excellent suggestions @EmmaButcher_ ! https://twitter.com/EmmaButcher_/status/1322834236194332672?s=20
Another great tip from @HarryMcCarthy, particularly for those missing libraries at the moment! https://twitter.com/HarryMcCarthy/status/1322834684246634496?s=20
So much good stuff in the @DesignMuseum shop, thanks for sharing @kmacostume! https://designmuseumshop.com/
This really does look very good, those apothecary bottle earrings are a dream!
https://twitter.com/BooksAndGuts/status/1322851947578347521?s=20
https://twitter.com/BooksAndGuts/status/1322851947578347521?s=20
Received a couple of recommendations for the @DickensMuseum shop - especially for Christmas presents! Thanks @ClaireWarrior1
and @_ChelseaPrice https://dickensmuseum.com/pages/curiosity-shop
and @_ChelseaPrice https://dickensmuseum.com/pages/curiosity-shop
I absolutely love @WhitworthArt, and they are taking phone orders from their lovely shop! https://twitter.com/taniahershman/status/1322877897804230656?s=20
Who better to support than the always wonderful @womenslibrary - and they have some very cool stuff in their online shop! Treat the feminists in your life. https://twitter.com/SueJohnGWL/status/1322912582160834561?s=20
I really love the @FarleysHG shop, definitely adding the Lee Miller fashion photography fish plates to my Christmas wish list! https://www.farleyshouseandgallery.co.uk/shop-overview/
Some lovely stuff here! https://shop.tate.org.uk/gifts-st-ives https://twitter.com/VickyWiltshire_/status/1322916502090166274?s=20
Another excellent small museum with online shop! https://twitter.com/florencemuseum/status/1322937305108271104
The excellent @NHM_London shop can be found here: https://www.nhmshop.co.uk/ https://twitter.com/piccoloexplorer/status/1322958228892823552?s=20
Really wanted to visit @HepworthGallery this year, will definitely be shopping here in lieu of a 2020 visit! https://shop.hepworthwakefield.org/ Thanks for the suggestion @catrionacurator.
Adding another of my own suggestions, @I_W_M has always been one of my favourite museums and their online shop is pretty extensive! https://shop.iwm.org.uk/
Thanks to @TommiesGuides for this recommendation! https://twitter.com/TommiesGuides/status/1322984403522510849?s=20
Books for adults and children available from the online shop of the @SlaveryMuseum https://shop.liverpoolmuseums.org.uk/collections/international-slavery-museum
Just discovered that @ShetlandMandA (which has been on my visit wish-list for a long time) has an online shop and just LOOK at this wee pin! Heaven. https://shop.shetlandwoolweek.com/collections/frontpage/products/katies-kep-pin
Check out the @balticgateshead shop here: https://twitter.com/rebryanshort/status/1323007951871889408
Totally love this recommendation, some amazing stuff here! https://twitter.com/thisaeshaw/status/1323015742678323201
Two museums I have very fond memories of visiting - with great shops too https://twitter.com/kjohnston92/status/1323023544264151040
https://twitter.com/kjohnston92/status/1323023544264151040
https://www.ditchlingmuseumartcraft.org.uk/shop/ https://twitter.com/andreapotts22/status/1323043903885479941
Want your own Lewis chessmen? https://shop.nms.ac.uk
Just noticed a lack of Welsh museums on this list. Adding the lovely @StFagans_Museum shop (love the Gwen John coaster sets) https://museum.wales/shop/
Check out the @RafMetheringham bookshop here https://twitter.com/rafmetheringham/status/1323325085692928001
https://twitter.com/rafmetheringham/status/1323325085692928001
@fairfax_house currently getting more up online, keep an eye out! https://twitter.com/fairfax_house/status/1323274207707516930
https://twitter.com/fairfax_house/status/1323274207707516930
More recommendations here! https://twitter.com/fairfax_house/status/1323274976007458817
