Lectures in sanskrit links

Nivedita                https://www.youtube.com/channel/UCpKcXfUiA5dMW_L2xdPw_Lg
Vyoma Samskrita Pathashala        https://www.youtube.com/channel/UCp5mvCwXR-drTRyzNUUjdZg
Abhinava-Vaiyakarana Sampradaya        https://www.youtube.com/channel/UC9QEyfWFwPvVeTnJpDusPCg
Samskrita Bharati            https://www.youtube.com/channel/UCIsVHnIfTrCbRu-CzV4abNA
                    https://www.youtube.com/channel/UCpL1Rk5hB_ufdvnYIAXG0jw
Viswasamskritam Samskritabharati    https://www.youtube.com/channel/UCoQX_P_FvGmD112y4AbH-ow
Samskrita Bharati USA            https://www.youtube.com/user/SamskritaBharatiUSA/videos
Karnataka Samskrit University        https://www.youtube.com/channel/UCi1DH73SA-cAicIC_lLK0XA/videos
sanskrit vishvam            https://www.youtube.com/channel/UCRYVVLSwQZNUWaHUshzkRoA
OnlineSamskrTutorial            https://www.youtube.com/user/OnlineSamskrTutorial/videos
Samskrita Shikshanam            https://www.youtube.com/channel/UC0hjxSl7vsrnYKuADFg1ITw/videos
Nyaya                     https://www.youtube.com/watch?v=a8XZdVDzLis&list=PL7_6YPlfLKeRttlUiKQFoIpM1eNhyhUmt
shastrarth programme            https://www.youtube.com/channel/UC-ds4_Ev_k4vE_ZqPS5ZWAQ
sudarshanhs                https://www.youtube.com/user/sudarshanhs/videos
Tikaram Pandeya                https://www.youtube.com/user/TIKARAMPANDEYA/videos
VISHWANATH DHITAL            https://www.youtube.com/channel/UClGCwPOQj7JCK57kvF3eTng/videos
व्याकरणसेतु                    https://www.youtube.com/channel/UCHX4Y3ftDSsxiIIUV9qQvjQ

There are also some other talks like this one by the Sringeri Swamiji:    https://www.youtube.com/watch?v=KbDmqTFsUcY

You may also search for Vakyaartha Goshthi, where top scholars discuss some shastra related subject and get some talks like: 
https://www.youtube.com/watch?v=D1Nov6_nX7k
https://www.youtube.com/watch?v=vbeDvGpHu7w
https://www.youtube.com/watch?v=SAvdu9N2ZGU
https://www.youtube.com/watch?v=CfSUM4B2hd8