I've had many calls from people with swallows or bats stuck to fly papers where they have been used outside under a shelter or open barn where people sit to eat and drink. Finally an obvious solution "found" on Facebook, either enclose the sticky fly-paper with chicken wire or put it in a mesh bird feeder.
Barbed wire should be avoided where ever possible if an alternative can be found. It's rarely necessary and stock fencing or electric tape is often a viable alternative . Owls and low flying raptors are frequent victims, the Long eared owl right died
This one is remarkably common, a snake getting entangled in netting, usually netting that has been left on the ground for clearing up later or perhaps simply discarded. In this case it's a Grass snake but I've had cases involving several different species. It's usually fatal because the snakes actions in trying to escape tighten the nylon more and more.
Open ended pipes, posts and chimneys are another constant source of trouble for birds and mammals that get in and can't get out. Consider wire mesh, chicken wire or some other type of grill.
Our wildlife comes under constant threat as a direct result of human activity and although it's not possible to live without harming other creatures there are a number of simple areas where we can take preventative actions without any loss to ourselves - little things will save lives.
Here we have some all too common issues but there will be many more you can think of I'm sure.