First, what will work with your 6D Mark II:
- EF 24-105mm f/4 L IS II
- Canon Speedlite 430EX II
- LP-E6 batteries and LC-E6 charger
- Cleaning supplies and bag
What might work with your 6D Mark II:
- Sigma 70-300mm f/4-5.6 DG if it is a recent enough copy to have firmware compatible with the 6D Mark II introduced in 2017. This lens has been around in various forms since the 1990s. The older versions have issues working with digital EOS cameras.¹ This lens may have been discontinued before the Canon EOS 6D Mark II was introduced. It's certainly no longer listed at Sigma's USA website.
- Wide Angle High Definition 0.45x lens with macro (if it has 58mm threads it will work on the Sigma 70-300mm lens, if it has 77mm threads it will work on the Canon 24-105mm.)
- Assorted filters (Filters with 77mm threads will work on the Canon 24-105mm f/4 L IS, filters with 58mm threads will work on the Sigma 70-300mm DG.)
¹ Mine, bought in the mid-1990s, had significant compatibility issues with my Canon EOS Rebel XTi. It still works on my Canon EOS film body, but I can use it on Canon digital bodies only as long as the camera is manually set to the lens' maximum aperture. If the camera is set to any other aperture when the camera attempts to stop down the lens it locks up the camera. The camera must be powered down and the battery removed to unlock the camera.
What won't work with your EOS 6D Mark II:
- Tamron AF 18-250 f/3.5-6.3 Di II (all Tamron Di II lenses are APS-C only)
- Battery Grip BG-E9 (It's made for the 60D, the 6D Mark II uses the BG-E21)
- Roller DSLR Pro Wide Converter with macro, 0.5x62mm (It's made to fit the Tamron 18-25mm)
Now, let's talk about all of that stuff.
This sounds like a list of stuff many online camera retailers offer as "kits" with a new camera. But the 60D is not a new camera. It was introduced back in 2010 and replaced by the 70D in 2013.
The only things of real value in that entire list are the Canon EOS 60D, the EF 24-105mm f/4 L IS, and the Canon 430EX II. The battery grip, if an original Canon version, is good but only for the 60D. This is assuming all of the above are in good shape and fully operational. Keep in mind that the 60D is an older model introduced in 2010 that has since been superseded by the 70D, 80D, and the current 90D.
The batteries and charger are useful, but don't cost that much, relatively speaking, to begin with. If they're third party batteries made before around 2014 or so, they probably won't be fully compatible with Canon bodies using firmware written since around 2014 when Canon updated their camera body firmware, both in new models and the newest versions of firmware for fairly recent models such as the 2012 5D Mark III, to call on parts of their battery protocol code that had previously remained "hidden" in the chips of all LP-E6 series of batteries. Older third party batteries will power the camera with whatever charge they're able to hold, but they won't communicate to the camera the exact percentage of charge remaining, the battery serial number, or the number of frames taken since the battery was last recharged. Plus even Canon batteries made before 2014 probably don't hold much of a charge any more. Rechargeable Li-Ion batteries eventually degrade to the point they will no longer take a charge. Part of that degradation is caused by use and recharging, but part of it is also a function of time, regardless of how heavy or lightly they've been used.
The Tamron 18-250mm f/3.5-6.3 Di II, also introduced in 2010, is a decent enough lens for the 60D if having a single, small, lightweight lens that is easy to carry everywhere is more important to you than optical image quality or wide enough apertures to shoot in low light.
The Sigma 70-300mm f/4-5.6 isn't that great of a lens and I doubt anyone with a 6D Mark II would be very happy with the results they would get using it with that camera. It was adequate for 4x6, 5x7, or even 8x10 prints made from 35mm film back in the day but not so much for the way we tend to view, i.e. pixel peep, high megapixel digital images.
That's if the Sigma 70-300mm f/4-5.6 even works with the 6D Mark II in terms of firmware. I would be extremely skeptical that it would until testing proves otherwise. Third party lenses are "reverse engineered" to work with the cameras already out at the time the lenses are designed. Camera models introduced after a third party lens is out sometimes have compatibility issues with those older lenses. Sometimes the lens maker will offer a firmware update, which for that lens would require a trip to a factory service center, but as long as that lens has been discontinued I doubt they'd even offer to do the last firmware update they issued for that lens, which may or may not be fully compatible with the 6D Mark II introduced in 2017. It's more likely to work with the EOS 60 introduced in 2010 if it was made in the last decade or so.
The "wide angle convertors" are, to put it nicely, junk. All of them.
Ditto for most sets of "various filters" included in such a package.
Ditto for most cleaning kits included in such packages.
The bag may or may not be usable for your purposes. LowePro is usually decent quality at a premium price, but a LowePro bag included in such a "deal" from most camera retailers will probably be a lot smaller than it looks in their listing.