Lemon and peppermint essential oils are good for URIs*, especially when breathed in with steam, and I found mine at the supermarket.
They smell much better than eucalyptus which I really dislike.
Olbas oil is another I've seen mentioned for use with URIs. "Olbas Oil contains a unique blend of six pure plant oils combining the essential oils of peppermint, eucalyptus, cajuput, clove, juniper berry and wintergreen with menthol (natural extract from the peppermint plant)." Though I'm not sure where I've seen it for sale.
Olbas Oil Active ingredients
* Formula (per ml)
* Eucalyptus Oil BP 0.2152ml Peppermint Oil BP 0.1693ml
* Cajuput Oil BPC 0.0478ml Turpentine Oil BP 0.0402ml
* Methyl Salicylate BP 0.0074ml Clove Oil BP 0.0040ml
I think I prefer lemon and peppermint which smells like a throat lozenge.
*To help breathing, but URIs definitely need vet care and antibiotics, for any newbies reading this.