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As a new hobbyist into the realm of photography my kit at the moment is rather unrefined. Currently I am still working through the various options in what to carry when running and gunning. Currently, my photography practice revolves around a rather broad assortment of environments and therefore have an equally varied requirements list. I may be roaming the streets of downtown, going by the city's waterway testing lenses, hiking, in the home studio, or at a sporting event. As a result I have utilized the PR1-e Thigh Bag to carry what I have deemed as essentials comfortably, discretely, low profile, movement unhindered, and at hands reach. 
Figure 1: PR1-e Thigh Bag Loaded for Photography
At the writing of this I use the Sony a7 ii Mirrorless Camera and own 5 total lenses; Sony 28-70mm f3.5-5.6 kit lens that came with the camera, 1961 Jupiter 8 50mm f2 (Zorki) through a Fotasy M39 to Sony E-Mount lens adapter, a 1963 Jupiter 12 35mm f2.8 (Kiev) through a Fotasy Nikon S/ Contax RF to Sony E-Mount lens adapter, a Tokina 50-250mm f4-5.6 through a Haoge Olympus OM to Sony E-Mount lens adapter, and a Tamron 85-210mm f4.5 through a Canon FD to Sony E-Mount lens adapter.
As the only non-vintage/ legacy lens that I own, the kit lens is my only option for having Auto-Focus at the moment. Because of that, new, unfamiliar, experimental, or time dependent environment it is the lens in which I tend to stick with. However, due to the compactness of the two Soviet prime lenses they both fit perfectly within just one of the "key" pockets (pockets B or C in Figure 1 B below).
Keeping the equipment in mint operating condition is vital both for their longevity as well as the quality of the final images produced (as I've been told). Therefore, I try to keep on top of this by taking a portion of the Cleaning kit with me, namely the air blower, cleaning cloths, spray bottle, and cleaning pen. (Albeit, I have yet to use anything other than the air puffer thankully). I will also bring some general electronics disposable wet wipes with me for the LCD display and viewfinder of the camera as well as general usage across my electronics (Not recommended for lenses or camera sensors).
Due to the notoriously poor battery life of the Sony a7 ii I have gotten two additional third party batteries and corresponding charging dock for it (Genuine Sony NP-fw50 batteries are cost prohibitive for me at the moment). Additional/ backup memory cards are also on hand, especially since they require such a limited footprint it just seems like a better safe than sorry thing to have.
A recent purchase is the Aputure AL-M9 LED video light which I have been experimenting with and been very pleased with thus far, an additional bonus is that the soft case in which it comes in allows for the organized storage of smaller miscellaneous items whilst still fitting in the "wallet pocket" (pocket F in Figure 1 below)
Figure 2: PR1-e Thigh Bag Pocket Sizing
Figure 3: Photography Loadout using PR1-e Thigh Bag