You really did not tell us anything about the ADC specs that you require. Various manufacturers like Analog Devices and TI have vast lines of products, including integrated parts that have PGA (programmable gain amplifier) front ends.
Here is a copy and paste from A TI webpage with a full scale input range in hundreds of millivolts.
"The ADS111x perform conversions at data rates up to 860 samples per second (SPS). The PGA offers input ranges from ±256 mV to ±6.144 V, allowing precise large- and small-signal measurements. The ADS1115 features an input multiplexer (MUX) that allows two differential or four single-ended input measurements. Use the digital comparator in the ADS1114 and ADS1115 for under- and overvoltage detection."
Don't give up yet. Keep searching. There are tons of devices out there.
Linear Technology was bought out by Analog Devices so it has a huge product line.
TI has been buying companies for years like Burr Brown and National Semiconductor so it;s product line is extremely large as well.
Here is the link for the TI product;
Again, you did not mention what, speed, resolution, etc. that you need so the above example may or may not be of interest to you.
Hope this helps a bit .....