Is DL1616 the same as CR1616?

Yes. DL1616 is another code for the same cell: lithium (Li-MnO2), 3 V, 16 × 1.6 mm.

Is ECR1616 the same as CR1616?

Yes. ECR1616 is another code for the same cell: lithium (Li-MnO2), 3 V, 16 × 1.6 mm.

Same 16 mm diameter, but 1.2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.

Same 16 mm diameter, but 2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.

No. Rechargeable Li-ion: 3.6-4.2 V and far less capacity; only for devices built for it.

CR1616 is a 3 V lithium cell with a typical capacity of 50–55 mAh.

CR1616 is the same cell as DL1616 and ECR1616, so any of those codes will fit; no other cell here is 16 × 1.6 mm at 3 V.

CR1616 at actual relative size: 16 mm across, 1.6 mm thick. The dashed circle is a US quarter, 24.26 mm across (US Mint coin specifications).

The same cell under another code. Any of these fits, whatever the brand.

Same diameter, different thickness. These are not drop-in replacements.

Cell	Size	Verdict
CR1612	16 × 1.2 mm	Same 16 mm diameter, but 1.2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.
CR1620	16 × 2 mm	Same 16 mm diameter, but 2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.
CR1632	16 × 3.2 mm	Same 16 mm diameter, but 3.2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.

These are the same size or a similar code, and they are not equivalents.

LIR1616
Rechargeable Li-ion: 3.6-4.2 V and far less capacity; only for devices built for it.

Used in automobile key remotes and in Game Boy cartridges (for powering the RAM for saved games).

Is DL1616 the same as CR1616?: Yes. DL1616 is another code for the same cell: lithium (Li-MnO2), 3 V, 16 × 1.6 mm.
Is ECR1616 the same as CR1616?: Yes. ECR1616 is another code for the same cell: lithium (Li-MnO2), 3 V, 16 × 1.6 mm.
Will CR1612 work in place of CR1616?: Same 16 mm diameter, but 1.2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.
Will CR1620 work in place of CR1616?: Same 16 mm diameter, but 2 mm tall instead of 1.6 mm. Only if the holder fits; thinner cells can lose contact.
Can I use LIR1616 instead of CR1616?: No. Rechargeable Li-ion: 3.6-4.2 V and far less capacity; only for devices built for it.
What voltage is CR1616?: CR1616 is a 3 V lithium cell with a typical capacity of 50–55 mAh.
What size is CR1616?: 16 mm across and 1.6 mm thick.