What tree is this?

Just getting into bonsai this year as I finally have a house to have bonsai so I putting a list of trees I would want to have. I can't seem to find what this is. This one is about 15' tall has like 1" thorns and red little fruit like a cotoneaster

Possibly Ilex decidua.

Some kind of hawthorn. Maybe 'Winter King'.

I'm with William. One of the million Hawthornes

I thought 'Hawthorn' at first glance too. How many seeds are in the fruit?

Ill have to check the seeds too I didn't know hawthorns grew so big, then again I'm a little new getting to bonsai

I googled both the ilex and the hawthorn varieties and the fruit is very similar, but the holly berry is almost closed on the end, to a dimple, and the Winter King berry is like yours, with the open end that is black.

Looks like this one goes to William!