Hello! Fellow POTS and chronic pain sufferer here.
I would find out if she already has a lot of these things. She likely already takes things to help her with POTS or has things like compression socks (and they just don’t make you feel sexy either) so I would go for something that will make her feel a bit more luxurious/like a queen on those really tough days. Things like a silk pillowcase, nice set of really comfortable Pajamas (I have bamboo ones and they make me feel great), some nice headphones so she can listen to music in bed in the mornings. Us with POTS cannot get out of bed fast so often have to slowly wake up.
One of the gifts my husband got me recently was a foot massage machine. It’s so so nice on days when I have to spend a lot of time sitting on the couch as I can just plug it in and get a nice relaxing foot massage. It’s also one of the only places on my body where I don’t have pain but do benefit from a rub. This is the exact one. Often people with POTS have increased calf pain from the poor blood circulation and blood pooling in our legs so it was actually a perfect gift for this condition and made me feel like a million bucks.
Some other things that are really nice that I have bought for myself were a massage gun and a Tens machine. Both of these have been extremely helpful! Only problem with the massage gun is that on days where things are difficult it becomes a bit of a chore to use it. I don’t have Trig so can’t comment on that one unfortunately.
I have a manur brand one, couldn't find it when I searched but its similar to this - https://www.amazon.ca/RENPHO-Massager-Compression-Fasciitis-Circulation/dp/B07F2H1NQR/ref=mp_s_a_1_3?dchild=1&keywords=marnur+foot+massager&qid=1629382299&sprefix=marnur+&sr=8-3
Works well, if its too strong turn it down. Shouldn't hurt.
I own this and use it once a week or so.
It's from Amazon.
Massage kit: - Foot massager with heat and air pressure. I got that one and it's amazing: https://www.amazon.com/RENPHO-Massager-Compression-Fasciitis-Circulation/dp/B07F2H1NQR - Eye massager with music via bluetooth, also amazing: https://www.amazon.com/RENPHO-Massager-Compression-Bluetooth-Rechargeable/dp/B07SM61FCT
RENPHO Foot Massager Machine with Heat, Shiatsu Deep Kneading, Compression, Relieve Foot Discomforts from Plantar Fasciitis https://www.amazon.com/dp/B07F2H1NQR/ref=cm_sw_r_cp_api_i_jmCwFbEX0SP8J
This thing saved my life.
I got this for my wife's birthday last month, she's at 28th week now and she likes it, she says it helps with her swollen feet