Boxing and Muay Thai both use similar gloves; the sports themselves are almost worlds apart.
The thumb is also often different on Boxing and Muay Thai gloves. On Boxing gloves, the thumb is normally kept as close to the fist as possible, protected behind the knuckle padding where possible. You can check this link https://everlastonline.eu/de/boxen/boxhandschuhe.html to buy best quality MMA gloves.
In boxing, you want to keep the thumb out of the way as much as possible to avoid it getting hit or injured.
The thumb is then usually either attached with a thin strip of material at the end of the thumb to keep it in place or fully attached with leather all the way up between the thumb and hand.
On a Muay Thai glove, acquiring the thumb somewhat 'tucked in' into the hand can help a whole lot with traction when grabbing and clinching.
The largest difference between the way Boxing and Muay Thai Boxing gloves is the use of this palm. In boxing, the hands are used for parrying shots, but in Muay Thai boxing that the fighters require the ability to grip in addition, as well as grabbing and holding kicks together with the palms.
In Boxing, gloves frequently attempt to match the wrist as tightly as possible, using a rather long match. The wrist does not normally take a massive amount of effect in boxing, which means that the priority is preventing the wrist from bending when hitting.
Muay Thai glove cuff is more comfortable and typically it's possible to get fairly excellent support by pulling on the strap tight.