Progress in element and chip design of single-mask bubble chips, based on drive-field operation, is reported. Three new elements, which have been successfully operated, are presented. (i) The replicator copies bubble streams for one propagation direction; when used in combination with the sense of rotation of the drive field it can serve as a bit generator. (ii) The λ-creator can selectively shift a bit over one propagation period. It can be applied in a decoder organization which permits rapid access to stored information. (iii) A current-controlled splitter-type generator was designed, which takes current pulses of about 60 mA for creating new bubbles.