In answer to Don MacInnes Several constructions of "free categories with X ", where X represents some sketch structure (i.e., data of cones and/or cocones to be transformed in limits and/or colimits) are given in the paper I wrote with Charles Ehresmann in 1972: "Categories of sketched structures", Cahiers de Topologie et Geometrie Differentielle XIII-2 (1972), p. 105-214. Reprinted in "Charles Ehresmann: Oeuvres completes et commentees" Part IV-2, Amiens 1982.. Some results are "on the nose", others only up to equivalence, and with preservation or not of some existing (co)limits. More or less different constructions are given in shorter papers reprinted in the 2 volumes of Part IV of these Oeuvres, as well as in the comments I have added on them (e.g. the comment p. 370 of Part IV-1), in which I also refer to results in this direction by other authors (up to 1982). Sincerely Andree C. Ehresmann