In a zone 8 climate, you are not limited to the groundcovers you can grow with the exception of those that won't tolerate high humidity (creeping thymes would be first on that list) - otherwise, it's your choice! You need to determine how much shade you have, what height you want, whether you want an evergreen GC, one that flowers, etc. The attached link is written for Georgia, but that only scratches the surface of possible groundcovers you could use. For a shady area, I'd add to that list pachysandra, lamium, sweet woodruff, hostas, epimediums, London Pride, and various spreading types of ferns.

Generally, any plant that spreads to cover large patches of soil can be used as a groundcover, but most folks tend to think in terms of very low growing plants. And be warned that what makes a plant a good GC - a growth habit that leans towards a rapid spread - is often viewed as an invasive nature, but with a few exceptions most can be controlled rather easily. Personally, I'd avoid English ivy as a GC - it is listed as a true invasive in many parts of the country, it is very difficult to eradicate once established and its dense growth provides a habitat for rodents.

Here is a link that might be useful: groundcovers for Georgia

I'm suprised you say that about creeping thyme. I am only in zone 7 but we just had a couple of very hot months (95-100 degree temps with 90-95% humidity) and my creeping thyme is doing great. The ones I planted last year are still blooming and the ones I planted this year are thriving.

JP

If you do a search on "thyme+humidity" you will get countless references to its intolerance for it. Herbs that originate from a Mediterranean climate generally prefer climate conditions that are mild and with very low humidity. They also prefer very lean and fast draining soils. Thymes, lavender, rosemary, etc. are typically not recommended for the deep south as high humidity encourages fungal problems which can be fatal and certainly disfiguring - generally they are considered pretty short lived plants under these conditions.

And since there is no shortage of other potential GC's the OP could use, planting something that is only going to be around a couple of years seems to be rather pointless and a waste of money.