Trash icon is crossed out
The meaning of this icon is obvious, never throw your iPhone into the trash despite how useless it is. The best way if you want to throw it away is sell, give, give or find a reliable recycling place.
See also: Looking at the people who bought the first iPhone X in the world, will soon return to Vietnam
Exclamation mark
An exclamation point means that the iPhone may not work as standard in some European countries. Perhaps there is no need to care.
Phone makers don't print the icons behind the device since 2014. Now, the iPhone 8 has the most 'clean' back. That's why you no longer see them on new iPhones but will find them on the iPhone box.