I do not understand TOML, but I think in YAML it should look like this:
params:
footwear:
coventry:
name: Coventry
alt_name: coventry
logo: coventry/coventry_1.jpg
logo_mini: coventry/coventry_1_thumb.jpg
{{ range .Site.Params.footwear}}
{{ .name }}
{{ .alt_name }}
{{ .logo }}
{{ end }}