For beginner bonsai enthusiasts:
my go-to is little book of bonsai and a ficus
Finally, the beginner's bonsai book you've been waiting for. Jonas Dupuich is one of North America's most highly accomplished bonsai artists, teachers and writers. Here's what Michael Hagedorn, author of Bonsai Heresy wrote about this exceptional new book: "We have waited a long time for a...
stonelantern.com
For intermediate:
A 25 pack of 3 gallon or larger grow bags are pretty nice. The 1 gallons are good for small starters. I like to roll the top over to make them a little shorter.
Root Pouch Charcoal Line is a 150g/m2 single-use fabric for commercial grow rooms. Lighter, more porous fabric than any other available. Root Pouch is the only fabric container company that offers natural fiber blended fabrics. This specific natural fiber blend offers superior drainage...
www.greenhousemegastore.com
It's also a good website for shade cloth if the bonsai person in your life is struggling with summer heat
Protect plants, equipment and people from high heat by hanging this purpose-designed fabric. We offer shade cloth and sail shades in the exact amount you need.
www.greenhousemegastore.com
A gift card to conifer kingdom for people who still have space to acquire more bonsai
NAPA DE Oil Dri, because you can never have too much growing media
M12 Hatchet for the Yamadori collector in your life
MILWAUKEE® M12 FUEL™ HATCHET™ 6" Pruning Saw Kit provides unmatched control & access. Includes: M12™ Battery, Charger, Oregon 6" Bar & Chain, Scabbard, Scrench
www.milwaukeetool.com
and the hackzall for root cutting
www.milwaukeetool.com
I like the M12 versions for portability but each has an M18 version if you want longer battery life.
full disclosure: I may work for said tool company so I'm very biased.
For advanced:
copper bonsai wire in different sizes. There are a lot of places to shop around but make sure it's annealed copper.