How to combine sfc objects from R package sf

Just use c like its a vector:

> (sfc12 = c(sfc1, sfc2))
Geometry set for 2 features 
geometry type:  POINT
dimension:      XY
bbox:           xmin: 0 ymin: 1 xmax: 1 ymax: 1
epsg (SRID):    NA
proj4string:    NA
POINT(0 1)
POINT(1 1)

And the length is 2:

> length(sfc12)
[1] 2

Drawing from @TimSalabim's answer, if your sfc objects are in the same CRS you can use

do.call(rbind, list(sfc1, sfc2)).