Maybe this is old news, and I'm not sure if many here play in 28mm, but I thought you all might be interested in this!
Immortal Miniatures is getting ready to release their first set of plastics, Hoplites, and it looks like maybe they have some Persians coming down the line too.
Additionally, Gripping Beast will be releasing a set of plastic Vikings sometime in the future. The announcement isn't linked on thier homepage, so here's a link to a WAB forum thread on them.
Lastly, while they're getting ready to release their plastic vikings, Wargames Factory are also working on a follow-up plastic set of Saxons.