Hi GregSilvia,
Welcome to Modular! :-)
Sorry if this might sound too direct, frank or even insulting, please believe me this is not what I intend. What I try though is making you aware and asking you, are you ready for modular? I just want to make sure that you don't buy something expensive and after a while you are not using it or even regretting it, that would be just a big pity.
In all my honesty, if you copy a rack of someone and take that as a starting point... I am not sure if you are ready for modular yet, are you? Are you really sure of yourself about this? You have to ask this in an honest moment yourself, please.
My point here is, if you take a copy of somebody's rack (and it doesn't matter which rack, for example the one you highlight here above), then you are taking a setup of a rack with the thoughts, planning and ideas of that person but for yourself without knowing these thoughts, planning and ideas this person had in mind. So you start with something you just don't know.
In my opinion, you should do a bit more research and indeed, it's okay to start with the modules used in this above example rack. Study those modules, try to understand them. Test them for example in VCV Rack. At a later stage and before you start buying, have them tested first at your local dealer.
Not sure how much experience you have with synthesizers in common, depending on that, you might want to go backward even a step and get to understand the basic principles of "simple" things like oscillators (VCOs), LFOs, envelopes (EGs or ADSRs), filters (VCFs), VCAs (amplifiers), attenuators and then slowly also move into logic modules, input/output modules, sequencers and the whole bim-bam :-)
But you might have all that, so let's assume you have that experience already or you are working on it and then let's go back to the above rack, let's assume you designed it :-)
It's certainly a nice compact and good looking rack. Some of those modules will get you something fancy, but that might not always be want you need or what you want. I miss in 'your' above rack some basic and classical components like the above mentioned items like envelopes, VCAs indeed, and more basic (or should I say easier to understand modules) LFOs and filters then used here. So you might want to look into that.
Also is the rack completely full, there is no space for future extension and for modular that's a very important thing, keep space free for future extensions. Plan a rack about half full for example, get some experience with it, get to know for yourself what you want, which module types you like, which brands you like and build on that experience extend your rack with more modules.
That having said, get a bigger rack than this. If I remember correctly I have seen messages here in the forum that this Intellijel case (2 x 84 HP 6U + 1U) is anyway sold out so get for example the 2*104 (7U) case from Intellijel (instead of the above rack), gives you a bit more space and allows you to easily extend it with an exact same case.
Looking at the above rack, you have to check those mixer modules, I am not sure what the intention was here but I think you can solve that a bit more elegant by using those 1U utility modules, that's why they are there for :-) And free up some "expensive" 3U space! :-)
So get rid of a few of those "fancy" modules, some of them are good and if you have a big rack why not taking them all? ;-) But you need to know their purposes to serve you the way you want. Rather get some space free for some "simple" basic stuff. Get a standard ADSR for example and indeed at least two VCAs (linear for CVs and exponential for audio; that's a general rule, it's not a must, discover for yourself why this general rule exist though).
That Magneto module, I have that one for a long time in my mind now, but A) I feel it's pretty expensive, is it worth it? B) I do think that's a module for perhaps not seniors but also not for beginners. A good reason for myself why I haven't bought it yet. My advice is to keep this module in mind when you are ready for it but leave it out when you start with modular. You got here a 2 x 84 HP rack = 168 HP, the Magneto is 28 HP that's rounded 17% of your total rack capacity! That's one sixth! Realising that, I would rather use this space for some more classic/basic/simple/other modules than such a fancy module. Don't get me wrong on "fancy module" please, I believe the Magneto is a fantastic module, but just not to start with if you are new in modular.
I think Plaits and STO, if you like them, you can keep them, those are pretty good modules, so that's a good start but please look into all the other functionality you require: LFOs, EGs, VCAs, VCFs, etcetera.
One more thing, the module choice here above is, for my personal taste, a slightly bit too much "digital". Lots of digital modules. Don't get me wrong, there is nothing against a good digital module! But almost only digital modules or at least a very high percentage on digital modules, are you sure that's what you want? I would say for Eurorack, analogue modules are very attractive and give you a bit more classical way of "building a synthesizer" because that's exactly what you do with modular. If you are happy with the high contents of digital modules, well then leave it as it is but my advice would be to focus a bit more (not only, digital is still good) on analogue modules.
I hope you didn't mind me being frank with you, I just want you to avoid to start in modular and then getting disappointed with what you get. I don't want you to leave with a depressive feeling, that's not good either. Modular is extremely fun and good but it requires quite some research and conceptional thinking of what you want to do with your modular system. And don't worry about to make mistakes that's so common within a modular synth, that's half of the fun (okay a quarter then ;-) ).
At first you might be a bit disappointed by a module because it unexpectedly didn't do or give you want you expected or wanted to do but leave it alone for a while and give it a few months later another chance once you build up more experience with the other modules you might have and then try it again and it might give you surprisingly possibilities you wouldn't have thought of the first time you used it :-) That's all possible within modular :-) And then there modules that are straight away from the beginning stars, those are the modules you are really looking for, this initial wow and addictive feeling that you can't live without them, not even a single day! :-)
So if you think you are ready, go for it and enjoy it! Don't be shy and ask if you need to know something.
Kind regards, Garfield Modular.
Edit: Removed a typo.
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads