I use as little as possible pg in my mixes and if I can sub out for an extract I will. MF, Real Flavors , OoO, and an occasionaly TFA have Pg free options. Just know on the TFA varieties they usually use Triacetin which is a plastic tank cracker...
As far as other alternatives I have read elsewhere different ideas on using Triethyl Citrate (Natural) https://shop.perfumersapprentice.com/p-8068-triethyl-citrate-natural.aspx where you would use the pg you''d plug in the TEC.... I have not tried it !!! Here is some discussion on it and it goes on further later on...someone did try it. I'd have to dig further more to find it.
TEC would be the emulsion or the colloidal blending the VG which is pretty tough to get all that flavor to bind with it that is why steeping is so crucial for a VG based juice.
If I had a homogenizer I could be for sure the flavors and the vg were actually " marrying " and not just well blended but at this time I am only using a magnetic mixer that , is in fact blending it to no end....plenty of white frothy bubbles going on stirring up a reaction with in the batch....you can of course shake it until you see fine bubbles there was a time I only had a USC and ultrasonic waves shake and of course cause a reaction in the batch as well as a large portion of these machines heat up as well and that's another reaction. I don't mix my batches with nicotine actually I have been nicotine free now for over a month but the point I am making that the heat would cause your nicotine to degrade after 120F it starts a degrading process.
Light oxygen heat time stirring blending these are all issues with steeping ejuice.
And don't get me started on using Distilled Water ( DW ) in your Vg mixes this is further more water down your batches. I did some trials a few summers ago and it was a flop it water downed the flavors and made the batch thin so that when I was trying to vape it I was getting a lot of spit back from the chimney. I would stay at 1% if you were to use it but I didn't find it successful.
MF - can be tricky to nail down %s vary greatly with each concentrate and can realistically be less is more with this brand.
RF SC- this brand is newer on the SC they first started out as a VG based flavor company and still do offer these but their SC I have a handful and feel theres still variety in %s used across the board some are as little as 0.5 % to 2-3%
OoO - One of One Not as large of an inventory as the above mentioned but % tend to be on the higher end around 3-8%
Having the equipment is another tricky issue for me as I vape MTL and above ohm so having the thick juice in a MTL set up can be problematic I tend to stick w/ Aspire Mini Nautilus and Tritions for this reason.
Good Luck to you man and if you come across another option feel free to let us know !