**3. Hybrid PSO algorithms using swarm intelligence**

Hybrid algorithms are quite successful since they combine both algorithms' powerful sides. Since PSO is quite fast algorithm, nearly all newly developed algorithm combined with PSO. Some of the recent studies using swarm intelligence are crow search algorithm (CSA) [27], ant lion optimizer (ALO) [28], the whale optimization algorithm (WOA) [29], grey wolf optimizer (GWO) [30], monarch butterfly optimization (MBO) [31], moth flame optimization [32], selfish herd optimization (SHO) [33], and salp swarm optimization (SSO) [34]. Since the algorithms stated in the following paragraph are quite new, according to the Web of Science records, there is not any hybrid study combining PSO with them.

Firefly algorithm (FFA) [35], bacterial foraging optimization algorithm (BFOA) [36], ant colony optimization (ACO) [37], artificial bee colony (ABC) [38], and cuckoo search (CS) [39] are some of the algorithms using swarm intelligence improved in the last decade. There are hybrid versions of these algorithms with PSO.
