he came by donkey vs he came on donkey

Some examples from the web:

• - He came by last night.
• He came by my place tonight...
• He came by to drop off some groceries.
• He came by to drop off some groceries.
• Well he came by last night, and he left.
• He came by to see Korsak.
• They said he came by this morning.
• He came by the job earlier today.
• He came by asking all sorts of questions.
• He came by expressly to accompany me to the Senate.
• I was closing the gate when he came by.
• A couple days ago he came by, and went running out the other side.
• No need to ask how he came by his wounds.
• He came by my place once.
• He came by a couple days later.
• No, he came by himself.
• He came by my shoot earlier and was so jealous.
• He came by this morning to help.
• He came by last week, Mickey did.
• He came by with it yesterday evening.

Some examples from the web:

• Christopher: once he came on board, the whole thing fell together.
• - He came on to me.
• But he came on Friday... and not Thursday.
• You know, he came on his own violation.
• I started recording before he came on.
• He came on Wednesday night to pick up his hockey sticks.
• I was talking to Stephen Fry about this when he came on a couple of weeks ago.
• I think he came on board under his own agenda.
• Dave Dryer, when he came on board, had the same philosophy.
• He came on to me when I was seeing someone.
• He came on to me, and then it got all awkward when I told him I had a boyfriend.
• I met VoIlhoffer at a party once... and he came on to me.
• He came on a surprise visit from Hawaii.
• He wasn't here long, so we can assume he came on a recent bus that day.
• He's alive and his first thought when he came on board this station was to plan a way to access your security files on the deuridium shipment.
• He came on to me in the bathroom...
• Yes, he came on to me, but unlike you, I controlled myself.
• He came on board, anyway, and every month we would meet.
• But that cop, your brother, he came on it and he ordered them to the ground.
• Because you did have to take a pay cut when he came on board.