Palenquero uses several copula, including:
e < Spanish es
ta < Spanish estar
sendá (etym. ?)
fue < Spanish fue
era < Spanish era
Note that fue can be used for both present and past (strange as this may be, from a Spanish perspective, where fue is always past).
It remains to be studied what "really" triggers speakers to use one over the other of these copulas.
Source: de Friedemann and Patiño Rosselli 1983: 131