The Collaboration Fund offers funding of up to £2,000 per partner involved. Activities must feature least one UK and one international partner. Anyone can apply to the Collaboration Fund, but you should ensure that there is only one nominated contact person for your work.
The Touring Fund offers funding of up to £2,000 per non-UK partner involved. It exists to support UK writers, but applications should be made by those intending to host them (i.e. non-UK festivals), not by the writers themselves.