Treating each in turn without too much electronics stuff:-
Analog-to-digital converter noise
Better known as quantization noise, is very simple as you can just leave an ADC input floating and the noise appears as a kinda rounding error. So that's a pro, but it is also difficult to measure correctly as other external noise sources can greatly influence it. This means that an entropy rate is difficult to assess that's due solely to quantization. You might be picking up old Fred next door using his arc welder.
No one really uses it as generation method in a standalone RNG device.
Better known as thermal noise is again very simple and the most common form of entropy. It's the majority of the hiss from an un tuned radio or the bulk of the static on an analogue TV. It's disadvantage is that it's very low level so requires large amplification to get useful entropy. This in turn makes the amplification susceptible to non random factors such as external interference.
The most notorious example of this entropy source is Intel's Ivy Bridge design. Linus Torvalds half believes in it, but I wouldn't trust it if you can't see it for yourself and you can't prove that it even exists.
Reverse biased semiconductor junction
Traditionally this is the most common DIY RNG technique, and a lot of the cheapo USB key type RNGs feature it. The pro is that it can generate a large entropy signal, but is inherently unstable over a monthly time period. Transistors are not designed to run backwards, so the entropy rate slowly degenerates.
Avalanche diode with optional atmospheric noise
Some confusion here. They don't really make specific avalanche diodes any more. The avalanche effect is particular to only certain Zener diodes. Atmospheric noise doesn't really figure in this. Your wiki link's reference to RF noise is simply an indication of the frequency of the noise such a diode makes.
The major advantage here is a relatively huge entropy signal that remains stable over time. You can get 1000s of bits/s of good entropy from such. This and web cam sensors are my favourite methods of entropy generation. The disadvantage is that the RNG has to be bulkier to accommodate higher voltage circuitry.
Modular entropy multiplication
More confusion. I'll try keep this appropriate for crypto rather than the electronics forum. Your link suggesting that MEM is "much easier to get right than other TRNGs" seems difficult to comprehend. Both the Infinite Noise TRNG and Z1FFER TRNG claim to follow Peter Allan's REDOUBLER design, yet they differ substantially. One even includes a so called avalanche diode, yet Allan's original design doesn't have one.
However, keeping an open mind (not a closed mind), I can accept that Allan's may have merit. Unless the whole thing's a scam, the results speak for themselves. It reminds me of a chaotic circuit, perhaps akin to a ring /phase shift oscillator but not quite. Chau circuits are another possible analogy. I have to admit though I've never heard of MEM and phase shift constructs are uncommon in standalone TRNGs. A stable chaotic circuit is something of an oxymoron.
1.5Mbps of 98.8% pure entropy is not to be sniffed at, although I'm uneasy. That's an amazing purity exceeding that from some optical beam splitters or even the fancier ones. I wonder how it was measured considering that non IID data's entropy is notoriously difficult to measure, and there is scant discussion of statistics, entropy characterisation or mathematics generally on the site. The golden rule of a TRNG (entropy out < entropy in) requires careful estimation of the raw rate. A histogram of $(u0i - u1i)$ would have been prudent, as would a correlogram. The absence of a true oscilloscope trace also sets off my spider sense. Needs further validation methinks.
By physical attack I take it to mean using a hammer. All commercial RNGs are susceptible to this and do not really make special provision against it other than the usual component encapsulation /shielding. Hardware security modules have more inbuilt protection, but those are not simple RNGs. Electronic attack can affect them but only as a form of service denial. The cryptographic avalanche effect of the entropy extraction process makes it impossible to force a hardware device to produce specific output.
The final pro of the avalanche effect method is that it's fairly simple to make a reliable DIY RNG if that's your bent. These are very amenable for operation in parallel with very little additional circuitry. You can cheaply increase the entropy rate eight fold by having eight or sixteen diodes. 5 megabit/s of raw entropy is easily possible. This is also the preferred choice of Bundesamt für Sicherheit in der Informationstechnik (BSI) AIS 20.