Here's a list of useful parts I've found on JLCPCB which are in their "basic" category for their PCB assembly service. These parts are definitely worth using in future designs since they are generally cheaper than buying them individually on DigiKey or Mouser, and they get assembled for no extended parts fee (1 USD).
I will update this with more detail as I find more useful parts or as I use the parts.
I found these using [JLC Parts](https://yaqwsx.github.io/jlcparts/#/) since the [official JLCPCB parts](https://jlcpcb.com/parts) website's parametric search isn't the greatest to say the least.
# Recommended ✅
## Capacitors, resistors, LEDs
You can find basics for most common SMD capacitors and resistors, including power supply decoupling and some which are used for matching networks. They also have some 0603 or 0805 LEDs for common colors. These are priced at bulk prices unlike buying them separately. Designing around placing these components is a no-brainer, as it saves the most manual soldering time.
## Inductors and ferrites
There is a limited selection of inductors and ferrites. I did not design around these since when designing a matching network you tend to use "weird" values which are not in the basics list. If you can substitute it though, definitely worth using the JLC ones.
## Microcontrollers
Almost always it is worth using JLCPCB instead of Digikey or Mouser for microcontrollers, even when using extended parts! The STM32F103 is a good deal. The STM32L151 is not that great for the price here, I would avoid it.
There are many linear regulators which are worth using. Some of them are quite outdated though (LM317)
## DC-DC converters
There are some buck, boost, and buck OR boost converters which are nice. However, there is no buck-boost converter on there.
## Battery management
There are some charging ICs for single-cell lithium ion batteries (TP4054, TP4056). Unfortunately there are no protection circuits but you should be able to implement one using operational amplifiers (also in basic parts) and a power MOSFET (not in basic parts unfortunately).
## Memory and storage
### W25Q128JVSIQ NOR flash (0.558$/1 units)
128 MBit SPI flash memory in a SOP-8 package. Drivers for the W25Q series are widely available.
### SN65HVD230DR CAN bus transceiver (0.742$/1 units)
1Mbps Transceiver SOIC-8 CAN ICs ROHS
Very cheap price. It is $2.55 USD on Mouser.
### RS232/RS422
I have not used these yet but I plan to use some RS232 transceivers in a future project (communication for my old Hitachi VC 6025 oscilloscope). I will update this if I finish that.
## Sensors
The only sensor in the basics parts category is the MPU-6050
### MPU-6050 (4.066$/1 units)
I don't recommend using the MPU-6050 since it is a very outdated accelerometer. Because it is old, however, it is very well supported and there are many libraries and code examples out there.
## ESD
### SRV05-4-P-T7 USB ESD protection (0.188$/1 units)
Very cheap ESD protection for your USB interface. Maximum VDD is 5V though, so you can't use it for higher voltages.
There are bridge rectifiers, optoisolators, magnetic isolators, operational amplifiers, darlington arrays, buffers, some logic ICs, analog switches, power diodes and small-signal MOSFETs available
# Not sure if these are useful ⚠
### FEMDRM008G-58A39 (3.079$/1 units)
7.28 GB eMMC in a 153 BGA package. Not sure if this is usable given the via minimum spacing of JLCPCB standard, or if this needs pad-in-via technology (which would raise the cost). If you can make this work with standard PCB, it would save a lot of cost.
I don't have first-hand experience using this chip, but my mate used it in a design and he said it just used so much power. This chip is also expensive compared to other options such as the CH340-E, which are only ~$0.4. Not much of a money-save this one.
# Wishlist for more basic parts
## Smaller button
Currently the only button in the basic parts is the TS-1187A-B-A-B. It has a HUGE footprint
I would like something smaller like these [oval shaped buttons](https://www.lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1089S-02526_C455282.html):
The only power converters in the basic list are buck converters, boost converters, or buck OR boost converter (controllers which can be configured as buck or boost depending on the components but cannot do both at the same time).
