Before getting to the links for the voiceover scripts, I want to briefly say write your own.
Write your own.
Freebies are great for practicing but if you want them for your reels, consider how many other people might have already used them for theirs.
Recording demo reels and keeping them current is obviously really important for voice artists. They push us to flex our muscles during the creative process and they help us to get work, so they have to be the absolute best we can possibly produce. That also means being unique. You won't stand out if you use a sample car commercial script that's been downloaded 145,000 times.
(By the time you finished reading that sentence, it was downloaded 3 more times).
But how do we even start writing our own, for a commercial reel, for example? Watch commercials. Lot's of them. If you don't have a TV, firstly, what do you point your sofa at? and secondly, take a look at this website. It's a huge library of great TV ads, with weekly updates. Absorb them like a sponge and use them as inspiration. Don't copy them, but allow them to give you some ideas of where you should aim for. Consuming media like this is always better than staring at a blank page trying frantically to write something for your reel. Listen to the words, the voice, and think about the content - service, product, charity etc.
Here's my commercial voice over demo. I wrote everything on here with my very own pencil.
You can do this for all your reels. Video production websites or Youtube (I'm not going to link to that, everybody knows it) are great for explainer video research. For radio ads... turn on the radio. Whatever scripts you need inspiration for, find that media.
If you want a charity ad on your commercial reel, watch some charity ads. What sort of words do they use? Are they hard sell or do they grab the audience a different way? Pull out some words you like and use a thesaurus to find other words like those. Use your own personal experiences to make the scripts real and human. (That's a good tip for voicing too, drawing on your history).
I'm not going to get into details about how to actually write the copy but just by doing a bit of leg work (eye and ear work), you can get a great start.
Use real brands - make the reel for what jobs you want to be doing. Like the ad for Dell? Make a Dell ad. Don't use Dave's Computers Down The Town (although I have heard VERY good things about them).
The last thing I'll mention about writing your own is how rewarding it can be. Seeing a script through from conception to the final edit with voice and music is a really great feeling.
OK FINE HERE'S SOME LINKS FOR FREE VOICE OVER SCRIPTS FOR YOUR DEMOS*.
But really, do have a go at writing your own. It's fun!