[Blink]

I'm using VMware Fusion and i use kali , ubuntu, centOS on it and they all seem to lag

The specs of the laptop i use it are:
2.9 GHz Intel Core i7
16 GB 1600 MHz DDR3
APPLE HDD ST750LM022 750 gb ( i will be upgrading to an SSD soon)
Intel HD Graphics 4000 1536 MB
on macOS Sierra

16GB of ram and It's lagging when running a VM?

If you're running simultaneous VMs, I can understand, but solely one VM with your current specs should function without any Issues whatsoever. That's provided there's no other resource-hungry applications active. How much memory have you allocated to the VM?

I just recently upgraded it to `16gb, before i had 8gb and i allocated 6gb to the VMs and I did run two VMs at the same time.

Dude... 6 + 6 + 1 (for host OS) > 8

Why would you even try that? You are allocating more RAM then you have.