Question What email closings do you use？

I'm often unsure of what's best to use for my (work) email closings so I'm curious what rules of thumb you all use.
For example, do most people just select a standard closing such as
以上、よろしくお願いします
and leave it at that? Or do you mix it up depending on what the contents of your mail is and who you're writing to?
For example even if it's not a request, do you still use よろしくお願いします? Or when do you decide to drop or include the 以上? Or maybe use 以上 only?

I use any number of variations, basically just going by whatever right given who I'm writing to, the nature of the communication (a request, asking a favor, an apology, etc.)

Just pulling up random emails from my sent box over the past few days:
以上、お手数をお掛けしますが、ご確認のほどよろしくお願いいたします。
それでは、引き続きよろしくお願いいたします。
ご迷惑をお掛けしますが、よろしくお願い申し上げます。
それでは、ご検討のほどよろしくお願いいたします。
今後とも何卒よろしくお願いいたします。
では、引き続きよろしくお願いします。
etc. etc.

Just from the above, you can probably gather a bit about the content of the email or the relationship with the recipient.
Even if it's not a request, per se, you really can't go wrong with a よろしくお願いします.
以上 isn't really required, and I typically only include it when I specifically want to (re-)call attention to what I've said above.

Just ending an email with 以上 only is very abrupt. I can see it in a brusque businesslike directive from a boss to subordinates, but as a freelancer corresponding directly with clients I wouldn't really have any occasion to close an email like that.

Thanks. You've clearly got that customer/client thing going on. There's nowhere near that level of variation between colleagues in my mailbox.

One of my coworkers has 以上 just above his signature, i.e. it's automatically added in every mail. So some of his mails will say よろしくお願いします before that, others may say something ありがとうございました and others won't say anything in particular, just some factual information like 追加しました。
I wonder if I should pay closer attention and be more mindful about when I choose お願いします vs お願いいたします。

Well, I mean it's really not that big of a deal. As a freelancer, I default to a fairly humble/polite register with clients (unless they're former co-workers/friends from my in-house days), but it's not like people would take extreme umbrage and rescind my contracts if I slipped a します in there in place of an いたします.

If this is in-house communication between fellow employees of the same company, it's even less important and there's really no reason that you'd _need_ to get any more polite than よろしくお願いします. (Though back in my corporate days I would use a more polite register with bosses, producers, and other bigwigs.)