それと details

Examples

and also; plus — a further item, added after the first has already been stated

牛乳ぎゅうにゅう買かってきて。それと、パンもお願ねがい。

gyuunyuu katte kite. soreto, pan mo onegai.

Pick up some milk. Oh, and bread too, please. casual

会議かいぎは三時さんじからです。それと、資料しりょうは各自かくじご用意よういください。

kaigi wa sanji kara desu. soreto, shiryou wa kakuji go youi kudasai.

The meeting starts at three. Also, please each bring your own copy of the materials. neutral

予約よやくの変更へんこうをお願ねがいします。それと、一点いってん伺うかがいたいことがあります。

yoyaku no henkou o onegai shimasu. soreto, itten ukagaitai koto ga arimasu.

I'd like to change my booking. And there's one thing I'd like to ask, as well. formal

それと belongs to speech and messages; a written notice adding a further
point uses また、 or なお、 instead.

それから
それから puts the second item after the first in TIME or in order (朝あさご飯はんを食たべて、それから出でかけた); それと adds an item with no order at all, which is why it is the one that works for an afterthought tacked onto a request.
それに
それに builds a case — the added fact pushes the same conclusion as the first (安やすい。それに近ちかい); それと argues nothing and simply adds one more entry to a list, so it can join two items that have no bearing on each other.
また
Same job of adding a further item, one register apart — また heads the added sentence in a notice or a report (また、次つぎの点てんにもご注意ちゅういください), それと belongs to speech and messages and would look careless in a printed announcement.

それとも
One kana apart and opposite jobs — それと adds a second item to what is already agreed (パンとミルク、それと卵たまごも), それとも makes the second an alternative to the first and needs a question around it; hearing one as the other turns a shopping list into a choice.